Demonstration of using Varnish with Docker

This is a simple docker setup for hosting and installing Magento2. The setup is based on https://gitlab.com/lumnn/magento2-docker-compose. I comes complete with sample data.

Please note:

• This setup is not using Adobe's Magento but the free variant MageOS.
• I also changed the base directory of Magento so there are no 2 git repos in the very same folder.
• The setup uses MageOS' sample data.
• The web server runs on ports 8080 and 8443 so port 80 and 443 is open for varnish.

Getting started

Clone the repo. Run the following commands

docker-compose up
./setup-magento.sh

After a few minutes, you will have a working Magento installation running on http://localhost:8080/

Useful Info About Magento 2

Admin Interface

Here is the admin URL and the corresponding access credentials.

http://localhost:8080/admin/
User: admin
Pasword: easy123

In case the admin login does not work, you can create a new admin account by calling

docker-compose exec -w /var/www/html php bin/magento admin:user:create

Accessing The Database

Use this command outside the docker container to get a mysql shell.

docker-compose exec db mysql -u magento -pmagento2 magento

Accessing The PHP instance shell

Find out how the web container is called:

docker ps | grep php | rev | cut -d ' ' -f1 | rev | grep -v "cron"

This will give you a list with all php containers. The one you're interested in is the one NOT having "cron" in the name. Depending on your docker and/or OS-setup the names you want to find will be something like

• varnished_magento_php_1
• varnished_magento-php-1

I'm using "varnished_magento_php_1" for the following examples. If your name differs, please adjust the commands accordingly.

If you need to access the shell on the web server:

## root access
docker exec -u root -it varnished_magento_php_1 /bin/bash

## app user access
docker exec -it varnished_magento_php_1 /bin/bash

E-mails

All emails from PHP containers can be seen in Mailhog at http://localhost:8025

Installing varnish

First, we install varnish on the php instance:

# ssh into instance
docker exec -u root -it varnished_magento_php_1 /bin/bash

# install varnish
apt-get update
apt-get -y install varnish

Next step, we go into the backend

# go into the backend
http://localhost:8080/admin/
    User: admin
    Pasword: easy123

Navigate to Stores -> Configuration -> Advanced -> System -> Full Page Cache. Switch "Caching Application" to "Varnish Cache". Click "Save Config".

Under Stores -> Configuration -> Advanced -> System -> Full Page Cache -> Varnish Configuration -> Export configuration you need to create a varnish config. Click on "Export VCL for Varnish 6". Store it on your computer.

Copy the file into the container

docker cp <vcls-file> varnished_magento_php_1:/etc/varnish/default.vcl

Then navigate to Stores -> Configuration -> General -> Web -> Base URLs and change the Base URL to "http://localhost/".

Or do it all on the command line:

bin/magento config:set --scope=default --scope-code=0 system/full_page_cache/caching_application 2

# generate varnish config
bin/magento varnish:vcl:generate --export-version=6 > /etc/varnish/default.vcl

# switch base url to varnish
bin/magento config:set web/unsecure/base_url http://localhost/
bin/magento cache:flush

# make sure the rights are correct (we ran bin/magento with root!)
chown -R app:app /var/www/html

Starting varnish

First, let's make it a little more interesting

# introduce an error into varnish config
sed -i 's/localhost/nginx/g' /etc/varnish/default.vcl

Start varnish

# start varnish
/usr/sbin/varnishd \
  -a :80 \
  -T localhost:8080 \
  -p feature=+http2 \
  -f /etc/varnish/default.vcl \
  -s malloc,2g

Debugging varnish

For the next step you need to open two shells, one root and one app shell

# open root shell
docker exec -u root -it varnished_magento_php_1 /bin/bash
# start varnish log
varnishlog

Visit http://localhost/ in your browser and see the website served by varnish. If everything works, you should see entries appearing in the Varnish-Log.

# open app shell
docker exec -it varnished_magento_php_1 /bin/bash
# clear cache
bin/magento cache:flush

Check the varnish log of the root shell. It should show a PURGE request but with the error "Method not allowed". This is because the requesting host does not match any of the allowed hosts.

# go to the root shell and stop varnishlog (CTRL-C)
# install a text editor (nano, vim, emacs, ...)
apt-get -y install nano

# install some debugging tools
apt-get -y install procps net-tools

# edit the varnish config
nano /etc/varnish/default.vcl

# find the Access Control List (acl) for purge and change the entry from "nginx" to "localhost"
acl purge {
    "localhost";
}

Now, save and exit the text editor. Now, we need to restart varnish:

ps aux | grep varnish

This will give you several entries. You want the one that has "varnish" in the first column. Check the PID in the second column.

# kill the process by PID
kill <PID>

Now, restart varnish

/usr/sbin/varnishd \
  -a :80 \
  -T localhost:8080 \
  -p feature=+http2 \
  -f /etc/varnish/default.vcl \
  -s malloc,2g

Open another root-shell and start varnishlog. Then, call "cache:flush" from the app shell and see, that the purge request passes sucessfully.

In case of emergency

If you need some debugging tools in the container

apt-get -y install procps nano net-tools