https://github.com/colinmollenhour/haproxy-service

A Docker container for HAProxy with auto-updating config based on DNS resolution (Docker Swarm, Kontena, etc).
https://github.com/colinmollenhour/haproxy-service

dns docker-image haproxy load-balancer

Last synced: 14 days ago
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A Docker container for HAProxy with auto-updating config based on DNS resolution (Docker Swarm, Kontena, etc).

• Host: GitHub
• URL: https://github.com/colinmollenhour/haproxy-service
• Owner: colinmollenhour
• Created: 2016-10-11T18:44:05.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2022-08-02T17:18:04.000Z (over 2 years ago)
• Last Synced: 2024-10-03T20:41:22.056Z (about 1 month ago)
• Topics: dns, docker-image, haproxy, load-balancer
• Language: Shell
• Homepage: https://hub.docker.com/r/colinmollenhour/haproxy-service/
• Size: 18.6 KB
• Stars: 3
• Watchers: 4
• Forks: 6
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# HAProxy Service Load Balancer

This container updates an HAProxy config template periodically using the results of DNS resolution

to trigger the update and apply the template and reload HAProxy.

## Usage

You can either run this container directly by mounting a template file at /etc/haproxy.cfg.tpl

or by copying and baking the template file in using a new Dockerfile. Either way it requires

an environment variable `SERVICE_HOSTNAME` which is the DNS name to resolve when updating the template.

Multiple DNS hostnames may be specified separated by commas.

#### Logging

HAProxy 1.9+ supports direct to stdout/stderr logging so rsyslog was removed.

#### User

This container runs as `root` rather than `haproxy` as it must write over the config file while running.

#### Usage

Run the image directly by mounting the config file as a volume:

    $ docker run \

      -e SERVICE_HOSTNAME=tasks.galera \

      -e UPDATE_FREQUENCY=10 \

      -v /path/to/your/haproxy.cfg.tpl:/etc/haproxy.cfg.tpl:ro \

      colinmollenhour/haproxy-service:2.6-alpine

Or build the config into the image:

    FROM colinmollenhour/haproxy-service:2.6-alpine

    COPY haproxy.cfg.tpl /etc/haproxy.cfg.tpl

    ENV SERVICE_HOSTNAME my-service

    ENV UPDATE_FREQUENCY 5

See the `samples/` directory for basic examples.

#### Template Format

Any block of text between the markers `{{HOSTS}}` and `{{/HOSTS}}` (must be on separate lines) will be rendered

in-place for each IP resolved by the `SERVICE_HOSTNAME`. The variables `$ip` and `$num` (the last octet of the `$ip`)

will be replaced accordingly. The IP addresses will always be sorted in the same order.

There may be multiple `{{HOSTS}} ... {{/HOSTS}}` blocks in the same template file.

Example:

    default-server inter 1s

    {{HOSTS}}

    server node${num} ${ip}:3306 check

    {{/HOSTS}}

If the `SERVICE_HOSTNAME` resolves to 10.0.0.12 and 10.0.0.20 it would render:

    default-server inter 1s

    server node12 10.0.0.12:3306 check

    server node20 10.0.0.20:3306 check

#### Init Scripts

If you need to run some basic scripts on init before the first template render mount or add a file at

`/docker-entrypoint-init.sh` which will be sourced by `docker-entrypoint.sh` once on startup.