Varnish-Image

Repo-Url: https://gitlab.com/strowi/varnish

Docker Image

Should be available on docker and gitlab:

• strowi/varnish:latest
• registry.gitlab.com/strowi/varnish:latest

containing

• Varnish 6.0.8
• Varnish-Modules
• libvmod-re
• varnish-exporter 1.6 listening on Port 9131.
• varnish_reload.sh: script to reload varnish-config
• be_state.sh: simple script to change backend-status (uses grep to find backend)
• varnishtop_metrics.sh: export top backend requests as prometheus metrics (node-exporter/textfile)

Opposed to other solutions the varnish-exporter is run in a separate container sharing /var/lib/varnish.

Usage

You can export variables that will be used to start varnish:

• BIND_PORT - port to bind to
• VCL_CONFIG - varnish config file to start
• VARNISHD_PARAMS - any additional parameter

This will start the docker-entrypoint.sh:

/usr/sbin/varnishd -P /var/run/varnishd.pid \
  -F \
  -a $BIND_PORT \
  -f $VCL_CONFIG \
  -s malloc,$CACHE_SIZE \
  $VARNISHD_PARAMS

Example: (docker-compose.yml)[./docker-compose.yml]

Updating Varnish-Config

Usually you don't want to restart the whole container for updates of the varnish-config because you would empty out the cache.

So we decided to create a separate folder for the configuration, sync that to the mounted ./src-folder. And then just run the following to reload the config:

~> docker-compose exec -T varnish varnish_reload.sh -m0 /etc/varnish/default.vcl

be_state.sh

Since above varnish_reload.sh appends a timestamp to the config-name each backends name changes with a config-reload:

> varnishadm backend.list
Backend name                   Admin      Probe                Last updated
reload_20210105_104634.backend1 probe      Healthy             3/3 Tue, 05 Jan 2021 10:46:38 GMT
reload_20210105_104634.backend2 probe      Healthy             3/3 Tue, 05 Jan 2021 10:46:38 GMT
reload_20210105_104634.backend3 probe      Healthy             3/3 Tue, 05 Jan 2021 10:46:38 GMT

This can get very annoying when you need to disable single backends. On multiple server even more so.

So be_state.sh takes a host and a status as argument and greps for the host settings the status.

~> be_state.sh backend1 sick
# looking for backend containing backend1
reload_20210105_104634.backend1
# setting varnish-backend on  to sick
~> varnishadm. backend.list
Backend name                   Admin      Probe                Last updated
reload_20210105_104634.backend1 probe      sick             3/3 Tue, 05 Jan 2021 10:46:38 GMT