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HA load-balancer with HTTP backends

Introduction

Deploy a highly-available Octavia load-balancer with its HTTP backends.

Stack architecture

to Heat or not

Theses Heat templates are directly inspired from this guide Load Balancers (Octavia). In case you prefer a manual setup, switch to that guide.

Features

  • HA load-balancing
  • HTTP health monitors
  • TLS termination
  • custom cloud-init
  • dedicated pools for SSH access

Project hierarchy

.
├── README.md
├── env.yaml
├── lib
│   ├── cloudinit.conf
├── nested
│   ├── backend.yaml
│   ├── listener.yaml
│   ├── pool-member.yaml
│   └── pool.yaml
└── template.yml

Prerequesites

CLI clients

To begin with make sure you have all the necessary clients installed.

Please refer to the OpenStack CLI clients

Keypair

Use the following command to ensure you have your keypair ready, the name should match the backends_key_name in env.yaml.

$ openstack keypair list
+-------------+-------------------------------------------------+------+
| Name        | Fingerprint                                     | Type |
+-------------+-------------------------------------------------+------+
| yubikey     | 32:32:75:2d:d1:02:d9:1f:a4:34:4b:ca:78:39:32:49 | ssh  |
+-------------+-------------------------------------------------+------+

If you have no keypair setup yet, please create one first using this guide.

Setup

First of all, clone the following repository : Infomaniak Github

The most important part is located in the env.yaml file. Make sure to review every parameter so that it suits you needs.

Parameters

Load-balancer are composed by multiple pieces of software, if you are not familiar with them we recommend you to first read Load Balancers (Octavia) guide.

Warning

In this section, parts of the stack parameters will be detailed by section but not all of them so it is recommended to review all of them in env.yaml

By default you get 3 HTTP backends.

If you wish to decrease / increase the number of backend do not forget to adjust the matching keys.

Warning

You may notice that some parameters seem to have odd values like pool_members_ports: 22,22,22,80,80,80 for instance. This is due to a Heat limitation when using a OS::Heat::ResourceGroup. For this reason a explanation is given along each parameters to make sure you get it right.

backends

Represent the instances where your workload resides

Parameter Default  Comment
backend_count 3
backends_key_name None
backends_prefix_name backend
backends_image Debian 10.11 buster if you use another distro, pay attention to cloud-init.conf
backends_flavor a1-ram2-disk20-perf1
backends_ips 10.8.1.11,10.8.1.12,10.8.1.13
backend_security_groups SSH,HTTP
security_groups_remote_ip_cidr_ssh 10.0.0.0/8 IP range to allow SSH from
security_groups_remote_ip_cidr_http 0.0.0.0/0 wide open

listeners

By default, with 3 backends the listener_count is 4 because you have 3 TCP listeners representing the dedicated SSH ports for each backend + 1 for the HTTP protocol that will obviously be load-balanced accross those 3 backends

Warning

Do not consider HTTPS here as it is handled separately

Parameter Default  Comment
 listener_count 4 number of backend + number of protocols ø SSH ø HTTPS
listeners_protocols TCP,TCP,TCP,HTTP 3 dedicated listeners for individual SSH access + HTTP
listeners_ports 2121,2222,2323,80 has to respect the order of listeners_protocols

pools

When it comes to the pools you have the same kind of logic.

Parameter Default  Comment
pool_count 4 number of backend + number of protocols ø SSH ø HTTPS
pools_protocols TCP,TCP,TCP,HTTP 3 dedicated pools for individual SSH access + HTTP
pools_load_balancer_algorithms SOURCE_IP,SOURCE_IP,SOURCE_IP,ROUND_ROBIN SOURCE_IP for the SSH and either ROUND_ROBIN or LEAST_CONNECTIONS for the HTTP.
pools_session_persistence SOURCE_IP,SOURCE_IP,SOURCE_IP,HTTP_COOKIE SOURCE_IP for the SSH and either HTTP_COOKIE or APP_COOKIE for the HTTP pool.

pool members

Parameter Default  Comment
pool_member_count 6 ( number of protocol ø HTTPS ) * number of backend
pool_members_addresses 10.8.1.11,10.8.1.12,10.8.1.13,10.8.1.11,10.8.1.12,10.8.1.13 here comes the nasty stuff. We have to do it this way because we need to map each SSH pool with its member and the HTTP pool with the N backend members
pool_members_pools pool-0,pool-1,pool-2,pool-3,pool-3,pool-3 the 3 first items are for the dedicated SSH and the 3 last one because we want to load-balance HTTP accross those N backends
pool_members_ports 22,22,22,80,80,80 accordingly you have 3 times SSH port and 3 times HTTP

If you use TLS termination and with to scale-up/down, do not forget to adjust those parameters as well. Hopefully this part is more simple.

Parameter Default  Comment
pool_member_tls_count 3 match the backend_count parameter
pool_members_tls_pools pool-https,pool-https,pool-https backend_count * pool_tls_name
pool_members_tls_addresses 10.8.1.11,10.8.1.12,10.8.1.13 report here backends_ips
pool_members_tls_ports 80,80,80 Even when using TLS the termination is done before so it speaks HTTP with the backends

TLS termination

By default the stack will create a TLS listener to terminate TLS connections, understand handling HTTPS requests.

Info

If you wish to skip that part and simply disable that feature set listener_tls_enabled: 'true' to false

In order to work there is an extra step "ex-catherda" to achieve, get the SSL certificate.

Either you have a valid, signed certificate or you want a self-signed one.

self-signed certificate (optional)

openssl req -newkey rsa:2048 -x509 -sha256 -days 365 -nodes \
            -out tls.crt -keyout tls.key \
            -subj "/CN=myloadbalancer-01.mydomain.infomaniak.cloud/emailAddress=myemail@infomaniak.ch"

Import the certificate

Before moving one you may need to convert a pkcs12 format.

Use the following command to convert a crt + key file to a pkcs12 one.

openssl pkcs12 -export -inkey tls.key -in tls.crt -passout pass: -out tls.p12

Then

base64 < tls.p12

Copy the output from this command and update secret_* parameters in env.yaml accordingly

Cloud-init

This project embed a custom cloud-init configuration file that do several things :

  • install apache2 package
  • enable SSH as root

    About SSH login

    Using some cloud images, new instances come up with a default user debian or ubuntu depending from the distribuion, which is the one you have to use to SSH as, then you can escalate as root using sudo su -.

    The given cloud-init configuration will let you use root to SSH. If you wish to bring back the default behavior feel free to adapt lib/cloud-init.conf.

  • remove unused / default cloud-init module like puppet, chef, salt-minion or phone-home

    Info

    Find more informations about cloud-init modules in the official cloud-init documentation

Deployment

Creating the stack

Once you have reviewed all the parameters you can pop-up the stack using the following command

% openstack stack create --wait -e env.yaml -t template.yml LB1

2021-12-29 15:09:42Z [LB1]: CREATE_IN_PROGRESS  Stack CREATE started
2021-12-29 15:09:43Z [LB1.security_group_http]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:43Z [LB1.security_group_http]: CREATE_COMPLETE  state changed
2021-12-29 15:09:44Z [LB1.secret]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:44Z [LB1.secret]: CREATE_COMPLETE  state changed
2021-12-29 15:09:45Z [LB1.security_group_ssh]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:45Z [LB1.security_group_ssh]: CREATE_COMPLETE  state changed
2021-12-29 15:09:46Z [LB1.router]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:47Z [LB1.load_balancer]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:48Z [LB1.network]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:48Z [LB1.network]: CREATE_COMPLETE  state changed
2021-12-29 15:09:48Z [LB1.subnet]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:49Z [LB1.subnet]: CREATE_COMPLETE  state changed
2021-12-29 15:09:49Z [LB1.servers]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:50Z [LB1.router]: CREATE_COMPLETE  state changed
2021-12-29 15:09:50Z [LB1.router_interface]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:09:53Z [LB1.router_interface]: CREATE_COMPLETE  state changed
2021-12-29 15:10:13Z [LB1.servers]: CREATE_COMPLETE  state changed
2021-12-29 15:11:38Z [LB1.load_balancer]: CREATE_COMPLETE  state changed
2021-12-29 15:11:38Z [LB1.listener_tls]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:11:38Z [LB1.listeners]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:11:44Z [LB1.listener_tls]: CREATE_COMPLETE  state changed
2021-12-29 15:11:44Z [LB1.pool_tls]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:11:50Z [LB1.pool_tls]: CREATE_COMPLETE  state changed
2021-12-29 15:11:50Z [LB1.pool_members_tls]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:12:13Z [LB1.listeners]: CREATE_COMPLETE  state changed
2021-12-29 15:12:13Z [LB1.pools]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:12:16Z [LB1.pool_members_tls]: CREATE_COMPLETE  state changed
2021-12-29 15:12:25Z [LB1.pools]: CREATE_COMPLETE  state changed
2021-12-29 15:12:25Z [LB1.pools_members]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:12:25Z [LB1.health_monitor]: CREATE_IN_PROGRESS  state changed
2021-12-29 15:12:29Z [LB1.health_monitor]: CREATE_COMPLETE  state changed
2021-12-29 15:12:56Z [LB1.pools_members]: CREATE_COMPLETE  state changed
2021-12-29 15:12:56Z [LB1]: CREATE_COMPLETE  Stack CREATE completed successfully
+---------------------+----------------------------------------------------------------------------------------------------+
| Field               | Value                                                                                              |
+---------------------+----------------------------------------------------------------------------------------------------+
| id                  | 954ed430-817f-487c-9fa9-f18f48507ac4                                                               |
| stack_name          | LB1                                                                                                |
| description         | Load-balancer stack with three HTTP backends, SSH access, HTTP health monitors and TLS termination |
| creation_time       | 2021-12-29T15:09:42Z                                                                               |
| updated_time        | None                                                                                               |
| stack_status        | CREATE_COMPLETE                                                                                    |
| stack_status_reason | Stack CREATE completed successfully                                                                |
+---------------------+----------------------------------------------------------------------------------------------------+

If you got so far you can issue the following command to get the entry point IP address of your stack.

% openstack stack show --fit-width -c outputs LB1
+---------+-----------------------------------------+
| Field   | Value                                   |
+---------+-----------------------------------------+
| outputs | - description: load-balancer IP address |
|         |   output_key: load-balancer-IP          |
|         |   output_value: 195.15.242.xx          |
|         | - description: website URL              |
|         |   output_key: website-URL               |
|         |   output_value: http://195.15.242.xx/  |
|         |                                         |
+---------+-----------------------------------------+

Ctrl / CMD + click on the link should bring you to the Apache2 default page. If so, have a piece of 🍰.

Updating the stack

Feel free to update any parameters and update the stack.

Info

If you scale-up/down, do not forget to adjust all necessary parameters accordingly, please refer to the Parameters section

openstack stack update --wait -e env.yaml -t template.yml LB1

Deleting the stack

If anything goes wrong you may want to delete the stack to restart from a clean state.

openstack stack delete --wait --yes LB1

References

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