1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
|
..
Copyright (c) 2016 IBM
Copyright 2019 Red Hat, Inc. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.
=============================
Basic Load Balancing Cookbook
=============================
Introduction
============
This document contains several examples of using basic load balancing services
as a tenant or "regular" cloud user.
For the purposes of this guide we assume that the neutron and barbican
command-line interfaces, via the OpenStack client, are going to be used to
configure all features of Octavia. In order to keep these examples short,
we also assume that tasks not directly associated with deploying load balancing
services have already been accomplished. This might include such things as
deploying and configuring web servers, setting up Neutron networks, obtaining
TLS certificates from a trusted provider, and so on. A description of the
starting conditions is given in each example below.
Please also note that this guide assumes you are familiar with the specific
load balancer terminology defined in the :doc:`../../reference/glossary`. For a
description of load balancing itself and the Octavia project, please see:
:doc:`../../reference/introduction`.
Examples
========
Deploy a basic HTTP load balancer
---------------------------------
While this is technically the simplest complete load balancing solution that
can be deployed, we recommend deploying HTTP load balancers with a health
monitor to ensure back-end member availability. See :ref:`basic-lb-with-hm`
below.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers.
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
.. _basic-lb-with-hm:
Deploy a basic HTTP load balancer with a health monitor
-------------------------------------------------------
This is the simplest recommended load balancing solution for HTTP applications.
This solution is appropriate for operators with provider networks that are not
compatible with Neutron floating-ip functionality (such as IPv6 networks).
However, if you need to retain control of the external IP through which a load
balancer is accessible, even if the load balancer needs to be destroyed or
recreated, it may be more appropriate to deploy your basic load balancer using
a floating IP. See :ref:`basic-lb-with-hm-and-fip` below.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTP application on TCP port 80.
* These back-end servers have been configured with a health check at the URL
path "/healthcheck". See :ref:`http-health-monitors` below.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers, and which
checks the "/healthcheck" path to ensure back-end member health.
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Create a health monitor on *pool1* which tests the "/healthcheck" path.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type HTTP --url-path /healthcheck --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
.. _basic-lb-with-hm-and-fip:
Deploy a basic HTTP load balancer using a floating IP
-----------------------------------------------------
It can be beneficial to use a floating IP when setting up a load balancer's VIP
in order to ensure you retain control of the IP that gets assigned as the
floating IP in case the load balancer needs to be destroyed, moved, or
recreated.
Note that this is not possible to do with IPv6 load balancers as floating IPs
do not work with IPv6.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTP application on TCP port 80.
* These back-end servers have been configured with a health check at the URL
path "/healthcheck". See :ref:`http-health-monitors` below.
* Neutron network *public* is a shared external network created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers, and which
checks the "/healthcheck" path to ensure back-end member health. Further, we
want to do this using a floating IP.
**Solution**:
1. Create load balancer *lb1* on subnet *private-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Create a health monitor on *pool1* which tests the "/healthcheck" path.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
6. Create a floating IP address on *public-subnet*.
7. Associate this floating IP with the *lb1*'s VIP port.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id private-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type HTTP --url-path /healthcheck --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
openstack floating ip create public
# The following IDs should be visible in the output of previous commands
openstack floating ip set --port <load_balancer_vip_port_id> <floating_ip_id>
Deploy a basic HTTP load balancer with session persistence
----------------------------------------------------------
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTP application on TCP port 80.
* The application is written such that web clients should always be directed to
the same back-end server throughout their web session, based on an
application cookie inserted by the web application named 'PHPSESSIONID'.
* These back-end servers have been configured with a health check at the URL
path "/healthcheck". See :ref:`http-health-monitors` below.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers, persists
sessions using the PHPSESSIONID as a key, and which checks the "/healthcheck"
path to ensure back-end member health.
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool which defines session
persistence on the 'PHPSESSIONID' cookie.
4. Create a health monitor on *pool1* which tests the "/healthcheck" path.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --session-persistence type=APP_COOKIE,cookie_name=PHPSESSIONID --wait
openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type HTTP --url-path /healthcheck --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy a TCP load balancer
--------------------------
This is generally suitable when load balancing a non-HTTP TCP-based service.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an custom application on TCP port 23456
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes requests to the back-end servers.
* We want to employ a TCP health check to ensure that the back-end servers are
available.
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Create a health monitor on *pool1* which probes *pool1*'s members' TCP
service port.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol TCP --protocol-port 23456 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol TCP --wait
openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type TCP --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy a QoS ruled load balancer
--------------------------------
This solution limits the bandwidth available through the Load Balancer's VIP by
applying a Neutron Quality of Service(QoS) policy to the VIP, so Load Balancer
can accept the QoS Policy from Neutron; Then limits the vip of Load Balancer
incoming or outgoing traffic.
.. note::
Before using this feature, please make sure the Neutron QoS extension(qos)
is enabled on running OpenStack environment by command
.. code-block:: console
openstack extension list
**Scenario description**:
* QoS-policy created from Neutron with bandwidth-limit-rules by us.
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer and want to limit the traffic
bandwidth when web traffic reaches the vip.
**Solution**:
1. Create QoS policy *qos-policy-bandwidth* with *bandwidth_limit* in Neutron.
2. Create load balancer *lb1* on subnet *public-subnet* with the id of
*qos-policy-bandwidth*.
3. Create listener *listener1*.
4. Create pool *pool1* as *listener1*'s default pool.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack network qos policy create qos-policy-bandwidth
openstack network qos rule create --type bandwidth_limit --max-kbps 1024 --max-burst-kbits 1024 qos-policy-bandwidth
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --vip-qos-policy-id qos-policy-bandwidth --wait
openstack loadbalancer listener create --name listener1 lb1 --protocol HTTP --protocol-port 80 --wait
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id <private_subnet_id> --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id <private_subnet_id> --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy a load balancer with access control list
-----------------------------------------------
This solution limits incoming traffic to a listener to a set of allowed
source IP addresses. Any other incoming traffic will be rejected.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an custom application on TCP port 23456
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes requests to the back-end servers.
* The application on TCP port 23456 is accessible to a limited source IP
addresses (192.0.2.0/24 and 198.51.100/24).
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1* with allowed CIDRs.
3. Create pool *pool1* as *listener1*'s default pool.
4. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol TCP --protocol-port 23456 --allowed-cidr 192.0.2.0/24 --allowed-cidr 198.51.100/24 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol TCP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy a non-terminated HTTPS load balancer
-------------------------------------------
A non-terminated HTTPS load balancer acts effectively like a generic TCP load
balancer: The load balancer will forward the raw TCP traffic from the web
client to the back-end servers without decrypting it. This means that the
back-end servers themselves must be configured to terminate the HTTPS
connection with the web clients, and in turn, the load balancer cannot insert
headers into the HTTP session indicating the client IP address. (That is, to
the back-end server, all web requests will appear to originate from the load
balancer.) Also, advanced load balancer features (like Layer 7 functionality)
cannot be used with non-terminated HTTPS.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with a TLS-encrypted web application on TCP port 443.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes requests to the back-end servers.
* We want to employ a TCP health check to ensure that the back-end servers are
available.
**Solution**:
1. Create load balancer *lb1* on subnet *public-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Create a health monitor on *pool1* which probes *pool1*'s members' TCP
service port.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTPS --protocol-port 443 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTPS --wait
openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type HTTPS --url-path /healthcheck --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 443 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 443 --wait pool1
.. _basic-tls-terminated-listener:
Deploy a TLS-terminated HTTPS load balancer
-------------------------------------------
With a TLS-terminated HTTPS load balancer, web clients communicate with the
load balancer over TLS protocols. The load balancer terminates the TLS session
and forwards the decrypted requests to the back-end servers. By terminating the
TLS session on the load balancer, we offload the CPU-intensive encryption work
to the load balancer, and enable the possibility of using advanced load
balancer features, like Layer 7 features and header manipulation.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with regular HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* A TLS certificate, key, and intermediate certificate chain for
www.example.com have been obtained from an external certificate authority.
These now exist in the files server.crt, server.key, and ca-chain.crt in the
current directory. The key and certificate are PEM-encoded, and the
intermediate certificate chain is multiple PEM-encoded certs concatenated
together. The key is not encrypted with a passphrase.
* We want to configure a TLS-terminated HTTPS load balancer that is accessible
from the internet using the key and certificate mentioned above, which
distributes requests to the back-end servers over the non-encrypted HTTP
protocol.
* Octavia is configured to use barbican for key management.
**Solution**:
1. Combine the individual cert/key/intermediates to a single PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *tls_secret1*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container.
5. Create pool *pool1* as *listener1*'s default pool.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
.. note::
A good security practise for production servers is to enable
HTTP Strict Transport Security (HSTS),
which can be configured during listener creation using the
``--hsts-max-age`` option and optionally ``--hsts-include-subdomains``
``--hsts-prefetch``.
Deploy a TLS-terminated HTTPS load balancer with SNI
----------------------------------------------------
This example is exactly like :ref:`basic-tls-terminated-listener`, except that
we have multiple TLS certificates that we would like to use on the same
listener using Server Name Indication (SNI) technology.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with regular HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* TLS certificates, keys, and intermediate certificate chains for
www.example.com and www2.example.com have been obtained from an external
certificate authority. These now exist in the files server.crt, server.key,
ca-chain.crt, server2.crt, server2.key, and ca-chain2.crt in the
current directory. The keys and certificates are PEM-encoded, and the
intermediate certificate chains are multiple certs PEM-encoded and
concatenated together. Neither key is encrypted with a passphrase.
* We want to configure a TLS-terminated HTTPS load balancer that is accessible
from the internet using the keys and certificates mentioned above, which
distributes requests to the back-end servers over the non-encrypted HTTP
protocol.
* If a web client connects that is not SNI capable, we want the load balancer
to respond with the certificate for www.example.com.
**Solution**:
1. Combine the individual cert/key/intermediates to single PKCS12 files.
2. Create barbican *secret* resources for the PKCS12 files. We will call them
*tls_secret1* and *tls_secret2*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container, and referencing both
*tls_secret1* and *tls_secret2* using SNI.
5. Create pool *pool1* as *listener1*'s default pool.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openssl pkcs12 -export -inkey server2.key -in server2.crt -certfile ca-chain2.crt -passout pass: -out server2.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack secret store --name='tls_secret2' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server2.p12)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --sni-container-refs $(openstack secret list | awk '/ tls_secret1 / {print $2}') $(openstack secret list | awk '/ tls_secret2 / {print $2}') --wait -- lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy a TLS-terminated HTTPS load balancer with client authentication
----------------------------------------------------------------------
With a TLS-terminated HTTPS load balancer, web clients communicate with the
load balancer over TLS protocols. The load balancer terminates the TLS session
and forwards the decrypted requests to the back-end servers. By terminating the
TLS session on the load balancer, we offload the CPU-intensive encryption work
to the load balancer, and enable the possibility of using advanced load
balancer features, like Layer 7 features and header manipulation.
Adding client authentication allows users to authenticate connections
to the VIP using certificates. This is also known as two-way TLS
authentication.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with a regular HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* A TLS certificate, key, and intermediate certificate chain for
www.example.com have been obtained from an external certificate authority.
These now exist in the files server.crt, server.key, and ca-chain.crt in the
current directory. The key and certificate are PEM-encoded, and the
intermediate certificate chain is multiple PEM-encoded certificates
concatenated together. The key is not encrypted with a passphrase.
* A Certificate Authority (CA) certificate chain and optional Certificate
Revocation List (CRL) have been obtained from an external certificate
authority to authenticate client certificates against.
* We want to configure a TLS-terminated HTTPS load balancer that is accessible
from the internet using the key and certificate mentioned above, which
distributes requests to the back-end servers over the non-encrypted HTTP
protocol.
* Octavia is configured to use barbican for key management.
**Solution**:
1. Combine the individual cert/key/intermediates to a single PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *tls_secret1*.
3. Create a barbican *secret* resource for the client CA certificate. We will
call this *client_ca_cert*.
4. Optionally create a barbican *secret* for the CRL file. We will call this
*client_ca_crl*.
5. Create load balancer *lb1* on subnet *public-subnet*.
6. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container, client authentication enabled,
*client_ca_cert* as the client CA tls container reference, and
*client_ca_crl* as the client CRL container reference.
7. Create pool *pool1* as *listener1*'s default pool.
8. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack secret store --name='client_ca_cert' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < client_ca.pem)"
openstack secret store --name='client_ca_crl' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < client_ca.crl)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --client-authentication=MANDATORY --client-ca-tls-container-ref=$(openstack secret list | awk '/ client_ca_cert / {print $2}') --client-crl-container=$(openstack secret list | awk '/ client_ca_crl / {print $2}') --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
.. _h2-alpn-tls-terminated-listener:
Deploy a secure HTTP/2 load balancer with ALPN TLS extension
------------------------------------------------------------
This example is exactly like :ref:`basic-tls-terminated-listener`, except that
we would like to enable HTTP/2 load balancing. The load balancer negotiates
HTTP/2 with clients as part of the TLS handshake via the Application-Layer
Protocol Negotiation (ALPN) TLS extension.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with regular HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* A TLS certificate, key, and intermediate certificate chain for
www.example.com have been obtained from an external certificate authority.
These now exist in the files server.crt, server.key, and ca-chain.crt in the
current directory. The key and certificate are PEM-encoded, and the
intermediate certificate chain is multiple PEM-encoded certs concatenated
together. The key is not encrypted with a passphrase.
* We want to configure a TLS-terminated HTTP/2 load balancer that is accessible
from the internet using the key and certificate mentioned above, which
distributes requests to the back-end servers over the non-encrypted HTTP
protocol.
* Octavia is configured to use barbican for key management.
**Solution**:
1. Combine the individual cert/key/intermediates to a single PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *tls_secret1*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container, and *h2* ALPN protocol ID and
*http/1.1* as fall-back protocol should the client not support HTTP/2.
5. Create pool *pool1* as *listener1*'s default pool.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --alpn-protocol h2 --alpn-protocol http/1.1 --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
Deploy HTTP and TLS-terminated HTTPS load balancing on the same IP and backend
------------------------------------------------------------------------------
This example is exactly like :ref:`basic-tls-terminated-listener`, except that
we would like to have both an HTTP and TERMINATED_HTTPS listener that use the
same back-end pool (and therefore, probably respond with the exact same
content regardless of whether the web client uses the HTTP or HTTPS protocol
to connect).
Please note that if you wish all HTTP requests to be redirected to HTTPS (so
that requests are only served via HTTPS, and attempts to access content over
HTTP just get redirected to the HTTPS listener), then please see `the example
<l7-cookbook.html#redirect-http-to-https>`__ in the :doc:`l7-cookbook`.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with regular HTTP application on TCP port 80.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* A TLS certificate, key, and intermediate certificate chain for
www.example.com have been obtained from an external certificate authority.
These now exist in the files server.crt, server.key, and ca-chain.crt in the
current directory. The key and certificate are PEM-encoded, and the
intermediate certificate chain is multiple PEM-encoded certs concatenated
together. The key is not encrypted with a passphrase.
* We want to configure a TLS-terminated HTTPS load balancer that is accessible
from the internet using the key and certificate mentioned above, which
distributes requests to the back-end servers over the non-encrypted HTTP
protocol.
* We also want to configure a HTTP load balancer on the same IP address as
the above which serves the exact same content (ie. forwards to the same
back-end pool) as the TERMINATED_HTTPS listener.
**Solution**:
1. Combine the individual cert/key/intermediates to a single PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *tls_secret1*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container.
5. Create pool *pool1* as *listener1*'s default pool.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
7. Create listener *listener2* as an HTTP listener with *pool1* as its
default pool.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 80 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 80 --wait pool1
openstack loadbalancer listener create --protocol-port 80 --protocol HTTP --name listener2 --default-pool pool1 --wait lb1
.. _pool-with-backend-reencryption:
Deploy a load balancer with backend re-encryption
-------------------------------------------------
This example will demonstrate how to enable TLS encryption from the load
balancer to the backend member servers. Typically this is used with TLS
termination enabled on the listener, but, to simplify the example, we are going
to use an unencrypted HTTP listener. For information on setting up a TLS
terminated listener, see the above section
:ref:`basic-tls-terminated-listener`.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTPS application on TCP port 443.
* A Certificate Authority (CA) certificate chain and optional Certificate
Revocation List (CRL) have been obtained from an external certificate
authority to authenticate member server certificates against.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers.
**Solution**:
1. Create a barbican *secret* resource for the member CA certificate. We will
call this *member_ca_cert*.
2. Optionally create a barbican *secret* for the CRL file. We will call this
*member_ca_crl*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1*.
5. Create pool *pool1* as *listener1*'s default pool, that is TLS enabled, with
a Certificate Authority (CA) certificate chain *member_ca_cert* to validate
the member server certificate, and a Certificate Revocation List (CRL)
*member_ca_crl* to check the member server certificate against.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack secret store --name='member_ca_cert' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < member_ca.pem)"
openstack secret store --name='member_ca_crl' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < member_ca.crl)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --enable-tls --ca-tls-container-ref $(openstack secret list | awk '/ member_ca_cert / {print $2}') --crl-container-ref $(openstack secret list | awk '/ member_ca_crl / {print $2}') --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 443 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 443 --wait pool1
Deploy a load balancer with backend re-encryption and client authentication
---------------------------------------------------------------------------
This example will demonstrate how to enable TLS encryption from the load
balancer to the backend member servers with the load balancer being
authenticated using TLS client authentication. Typically this is used with TLS
termination enabled on the listener, but, to simplify the example, we are going
to use an unencrypted HTTP listener. For information on setting up a TLS
terminated listener, see the above section
:ref:`basic-tls-terminated-listener`.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTPS application on TCP port 443.
* A Certificate Authority (CA) certificate chain and optional Certificate
Revocation List (CRL) have been obtained from an external certificate
authority to authenticate member server certificates against.
* A TLS certificate and key have been obtained from an external Certificate
Authority (CA). The now exist in the files member.crt and member.key. The
key and certificate are PEM-encoded and the key is not encrypted with a
passphrase (for this example).
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes web requests to the back-end servers.
**Solution**:
1. Combine the member client authentication certificate and key to a single
PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *member_secret1*.
3. Create a barbican *secret* resource for the member CA certificate. We will
call this *member_ca_cert*.
4. Optionally create a barbican *secret* for the CRL file. We will call this
*member_ca_crl*.
5. Create load balancer *lb1* on subnet *public-subnet*.
6. Create listener *listener1*.
7. Create pool *pool1* as *listener1*'s default pool, that is TLS enabled, with
a TLS container reference for the member client authentication key and
certificate pkcs12, also with a Certificate Authority (CA) certificate chain
*member_ca_cert* to validate the member server certificate, and a
Certificate Revocation List (CRL) *member_ca_crl* to check the member server
certificate against.
8. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey member.key -in member.crt -passout pass: -out member.p12
openstack secret store --name='member_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < member.p12)"
openstack secret store --name='member_ca_cert' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < member_ca.pem)"
openstack secret store --name='member_ca_crl' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < member_ca.crl)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --enable-tls --ca-tls-container-ref $(openstack secret list | awk '/ member_ca_cert / {print $2}') --crl-container-ref $(openstack secret list | awk '/ member_ca_crl / {print $2}') --tls-container-ref $(openstack secret list | awk '/ member_secret1 / {print $2}') --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 443 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 443 --wait pool1
Deploy a HTTP/2 load balancer with ALPN TLS extension and backend re-encryption
-------------------------------------------------------------------------------
This example will demonstrate how to enable HTTP/2 load balancing. We deploy
the same h2 alpn protocol and TLS terminated listener that we use in
:ref:`h2-alpn-tls-terminated-listener` and we deploy the same pool and members
with backend re-encryption and h2 alpn protocols that we use in
:ref:`pool-with-backend-reencryption`.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an HTTPS application on TCP port 443.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* A TLS certificate, key, and intermediate certificate chain for
www.example.com have been obtained from an external certificate authority.
These now exist in the files server.crt, server.key, and ca-chain.crt in the
current directory. The key and certificate are PEM-encoded, and the
intermediate certificate chain is multiple PEM-encoded certs concatenated
together. The key is not encrypted with a passphrase.
* We want to configure a TLS-terminated HTTP/2 load balancer that is accessible
from the internet using the key and certificate mentioned above, which
distributes requests to back-end servers.
* Octavia is configured to use barbican for key management.
**Solution**:
1. Combine the individual cert/key/intermediates to a single PKCS12 file.
2. Create a barbican *secret* resource for the PKCS12 file. We will call
this *tls_secret1*.
3. Create load balancer *lb1* on subnet *public-subnet*.
4. Create listener *listener1* as a TERMINATED_HTTPS listener referencing
*tls_secret1* as its default TLS container, and *h2* ALPN protocol ID and
*http/1.1* as fall-back protocol should the client not support HTTP/2.
5. Create pool *pool1* as *listener1*'s default pool, that is TLS enabled, and
*h2* ALPN protocol ID and *http/1.1* as fall-back protocol should the
client not support HTTP/2.
6. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.crt -passout pass: -out server.p12
openstack secret store --name='tls_secret1' -t 'application/octet-stream' -e 'base64' --payload="$(base64 < server.p12)"
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --protocol-port 443 --protocol TERMINATED_HTTPS --alpn-protocol h2 --alpn-protocol http/1.1 --name listener1 --default-tls-container=$(openstack secret list | awk '/ tls_secret1 / {print $2}') --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP --enable-tls --alpn-protocol h2 --alpn-protocol http/1.1 --wait
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 443 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 443 --wait pool1
Deploy a UDP load balancer with a health monitor
------------------------------------------------
This is a load balancer solution suitable for UDP-based services.
**Scenario description**:
* Back-end servers 192.0.2.10 and 192.0.2.11 on subnet *private-subnet* have
been configured with an application on UDP port 1234.
* Subnet *public-subnet* is a shared external subnet created by the cloud
operator which is reachable from the internet.
* We want to configure a basic load balancer that is accessible from the
internet, which distributes requests to the back-end servers.
* We want to employ a UDP health check to ensure that the back-end servers are
available. UDP health checks may not work correctly if ICMP Destination
Unreachable (ICMP type 3) messages are blocked by a security rule (see
:ref:`other-health-monitors`).
**Solution**:
1. Create load balancer *lb1* on subnet *private-subnet*.
2. Create listener *listener1*.
3. Create pool *pool1* as *listener1*'s default pool.
4. Create a health monitor on *pool1* which connects to the back-end servers.
5. Add members 192.0.2.10 and 192.0.2.11 on *private-subnet* to *pool1*.
**CLI commands**:
::
openstack loadbalancer create --name lb1 --vip-subnet-id public-subnet --wait
openstack loadbalancer listener create --name listener1 --protocol UDP --protocol-port 1234 --wait lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol UDP --wait
openstack loadbalancer healthmonitor create --delay 3 --max-retries 2 --timeout 2 --type UDP-CONNECT --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.10 --protocol-port 1234 --wait pool1
openstack loadbalancer member create --subnet-id private-subnet --address 192.0.2.11 --protocol-port 1234 --wait pool1
.. _health-monitor-best-practices:
Health Monitor Best Practices
=============================
An Octavia health monitor is a process that does periodic health checks on each
back-end member to pre-emptively detect failed members and temporarily
pull them out of the pool.
If the health monitor detects a failed member, it removes it from the pool and
marks the member in ERROR. After you have corrected the member and it is
functional again, the health monitor automatically changes the status of the
member from ERROR to ONLINE, and resumes passing traffic to it.
Always use health monitors in production load balancers. If you do not have a
health monitor, failed members are not removed from the pool. This can lead to
service disruption for web clients.
See also the command, `loadbalancer healthmonitor create <https://docs.openstack.org/python-octaviaclient/latest/cli/index.html#loadbalancer-healthmonitor-create>`_.
.. _all-health-monitors:
Configuration arguments for all health monitors
-----------------------------------------------
All health monitor types for Octavia require the following configurable
arguments:
* ``delay``: Number of seconds to wait between health checks.
* ``timeout``: Number of seconds to wait for any given health check to
complete. ``timeout`` should always be smaller than ``delay``.
* ``max-retries``: Number of subsequent health checks a given back-end
server must fail before it is considered *down*, or that a failed back-end
server must pass to be considered *up* again.
.. _http-health-monitors:
Configuration arguments for HTTP health monitors
------------------------------------------------
In addition to the arguments listed earlier in :ref:`all-health-monitors`, HTTP
health monitor types *also* require the following arguments, which are set by
default:
* ``url-path``: Path part of the URL that should be retrieved from the back-end
server. By default this is "/".
* ``http-method``: HTTP method that should be used to retrieve the
``url-path``. By default this is "GET".
* ``expected-codes``: List of HTTP status codes that indicate an OK health
check. By default this is just "200".
For a complete list of configuration arguments for Octavia health monitors, see
the command, `loadbalancer healthmonitor create <https://docs.openstack.org/python-octaviaclient/latest/cli/index.html#loadbalancer-healthmonitor-create>`_.
Please keep the following best practices in mind when writing the code that
generates the health check in your web application:
* The health monitor ``url-path`` should not require authentication to load.
* By default the health monitor ``url-path`` should return a HTTP 200 OK status
code to indicate a healthy server unless you specify alternate
``expected-codes``.
* The health check should do enough internal checks to ensure the application
is healthy and no more. This may mean ensuring database or other external
storage connections are up and running, server load is acceptable, the site
is not in maintenance mode, and other tests specific to your application.
* The page generated by the health check should be very light weight:
* It should return in a sub-second interval.
* It should not induce significant load on the application server.
* The page generated by the health check should never be cached, though the
code running the health check may reference cached data. For example, you may
find it useful to run a more extensive health check via cron and store the
results of this to disk. The code generating the page at the health monitor
``url-path`` would incorporate the results of this cron job in the tests it
performs.
* Since Octavia only cares about the HTTP status code returned, and since
health checks are run so frequently, it may make sense to use the "HEAD" or
"OPTIONS" HTTP methods to cut down on unnecessary processing of a whole page.
.. _other-health-monitors:
Other health monitors
---------------------
Other health monitor types include ``PING``, ``TCP``, ``HTTPS``, ``SCTP``,
``TLS-HELLO``, and ``UDP-CONNECT``.
``PING`` health monitors send periodic ICMP PING requests to the back-end
servers. Obviously, your back-end servers must be configured to allow PINGs in
order for these health checks to pass.
.. warning::
Health monitors of type ``PING`` only check if the member is reachable and
responds to ICMP echo requests. It will not detect if your application
running on that instance is healthy or not. Most pools should use one of
the other health monitor options. ``PING`` should only be used in specific
cases where an ICMP echo request is a valid health check.
``TCP`` health monitors open a TCP connection to the back-end server's protocol
port. Your custom TCP application should be written to respond OK to the load
balancer connecting, opening a TCP connection, and closing it again after the
TCP handshake without sending any data.
``HTTPS`` health monitors operate exactly like HTTP health monitors, but with
ssl back-end servers. Unfortunately, this causes problems if the servers are
performing client certificate validation, as HAProxy won't have a valid cert.
In this case, using ``TLS-HELLO`` type monitoring is an alternative.
``SCTP`` health monitors send an INIT packet to the back-end server's port.
If an application is listening on this port, the Operating System should reply
with an INIT ACK packet, but if the port is closed, it replies with an ABORT
packet.
If the health monitor receives an INIT ACK packet, it immediately closes the
connection with an ABORT packet, and considers that the server is ONLINE.
``TLS-HELLO`` health monitors simply ensure the back-end server responds to
SSLv3 client hello messages. It will not check any other health metrics, like
status code or body contents.
``UDP-CONNECT`` health monitors do a basic UDP port connect. Health monitors
of this type may not work correctly if Destination Unreachable (ICMP type 3) is
not enabled on the member server or is blocked by a security rule. A member
server may be marked as operating status ONLINE when it is actually down.
Intermediate certificate chains
===============================
Some TLS certificates require you to install an intermediate certificate chain
in order for web client browsers to trust the certificate. This chain can take
several forms, and is a file provided by the organization from whom you
obtained your TLS certificate.
PEM-encoded chains
------------------
The simplest form of the intermediate chain is a PEM-encoded text file that
either contains a sequence of individually-encoded PEM certificates, or a PEM
encoded PKCS7 block(s). If this is the type of intermediate chain you have been
provided, the file will contain either ``-----BEGIN PKCS7-----`` or
``-----BEGIN CERTIFICATE-----`` near the top of the file, and one or more
blocks of 64-character lines of ASCII text (that will look like gobbedlygook to
a human). These files are also typically named with a ``.crt`` or ``.pem``
extension.
DER-encoded chains
------------------
If the intermediates chain provided to you is a file that contains what appears
to be random binary data, it is likely that it is a PKCS7 chain in DER format.
These files also may be named with a ``.p7b`` extension.
You may use the binary DER file as-is when building your PKCS12 bundle:
::
openssl pkcs12 -export -inkey server.key -in server.crt -certfile ca-chain.p7b -passout pass: -out server.p12
... or you can convert it to a series of PEM-encoded certificates:
::
openssl pkcs7 -in intermediates-chain.p7b -inform DER -print_certs -out intermediates-chain.crt
... or you can convert it to a PEM-encoded PKCS7 bundle:
::
openssl pkcs7 -in intermediates-chain.p7b -inform DER -outform PEM -out intermediates-chain.crt
If the file is not a PKCS7 DER bundle, either of the two ``openssl pkcs7``
commands will fail.
Further reading
===============
For examples of using Layer 7 features for more advanced load balancing, please
see: :doc:`l7-cookbook`
|