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Synology: How do I update an existing Docker container with a new image?

As always: before you do such an update, make sure to create a backup of all your files. If something goes wrong, this may lead to data loss!

Manual update

To update an existing Docker container manually, the following steps are necessary;

Go to Registry and download new image (mostly the “latest” version)
Go to Container, select the container you need to update and stop it
From Actions menu select “Clear”
Edit: Under DSM7, the “Clear” command has been renamed “Reset”.
Start the container again

This will clear the complete container and start with the newly downloaded Docker image. Since the data folders are mounted into the container, this will not erase the apllications data. Configurations are also not affected by this.

Side note: when updating a major version of gitlab/gitlab-ce, make sure to follow the update paths! This requires updates in smaller steps (minor versions).

Automatically update Docker images

Updating a Docker image manually might be fine for a small number of images. But there is a more elegant way by using another Docker container called Watchtower. This one can update Docker containers automatically. The image is called containrrr/watchtower. A simple setup can be performed with the following steps:

Load image containrrr/watchtower in the Docker registry
Sign in with root privilege via SSH
Run the following code in the shell:

docker run -d --network host --name watchtower-once -v /var/run/docker.sock:/var/run/docker.sock containrrr/watchtower:latest --cleanup --include-stopped --run-once

This will start the Watchtower image and update all container once. The container created for this runs once and can then be found switched off in the list of containers. Now you can start it manually again and again as needed or let it run at certain times via Synology Task Scheduler. The command for the task scheduler is then as follows:

docker start watchtower-once -a

Let Watchtower run permanently

Alternatively you can use the scheduler in Watchtower itself. If you want to start it every Monday at 4 a.m., then enter the following command on the shell:

docker run -e "TZ=Europe/Berlin" -d --restart unless-stopped --network host --name watchtower -v /var/run/docker.sock:/var/run/docker.sock containrrr/watchtower --cleanup --include-stopped --schedule "0 0 4 ? * MON"

It is important to set the time zone to your because otherwise you will have an offset to UTC. In addition, the container is not terminated but always restarted. Even if it crashed or the NAS was restarted. The last parameter uses the cron syntax for scheduling the task.

Photo by sergio souza on Unsplash

Run GitLab console on Synology NAS

Posted by Mathias Lipowski
GitLab / Leave a comment Tags: Console, GitLab, Synology

As the Synology DSM uses Docker to run GitLab, we can use Docker as well to install GitLab Runner. For this, connect to the Synology using SSH:

ssh <admin-user>@<synology> -p <port>

To connect to the GitLab container, you can use the following command to open:

docker exec -it synology_gitlab /bin/bash

You might adjust the name of the GitLab docker depending on your system.

To open the console, run:

gitlab-rails console

When GItLab is installed using the DSM package manager, just use the following commands:

cd /home/git/gitlab/bin
./rails console production

Commands for the console

Below are some examples how to use the GitLab console.

Check the mail delivery method

ActionMailer::Base.delivery_method

Output might be: => :smtp

Check the smtp settings

ActionMailer::Base.smtp_settings

Output might be: => {:address=>"example.com", :port=>25, …

Testing the SMTP configuration (see documentation)

Notify.test_email('mail@example.com', 'Subject', 'Mail Body').deliver_now

GitLab on Synology: set ‘external_url’

Posted by Mathias Lipowski
GitLab / 1 Comment Tags: GitLab, Synology

There are two (or even more) solutions to install GitLab on a Synology:

Using Docker and the container gitlab/gitlab-ce
Using the DSM package manager

Depending on the type of installation, different settings are required to update the external url.

Using Docker container

The external url of GitLab can e defined in /etc/gitlab/gitlab.rb. The parameter takes an url and can also handle a port:

external_url 'http://example.synology.me:30000/'

Important: when a port is specified in external_url, this will override the https/https port where nginx is listening. To use a different port for nginx, this requires an additional setting:

nginx['listen_port'] = 80

After changing this setting, it’s necessary to run:

gitlab-ctl reconfigure

The settings above are necessary, if port routing is set like the following:

Using DSM package manager installation

This installation of GitLab on Synology uses localhost as a default value for external url. This may lead to some problems when accessing GitLab over another IP or host name. In my case, this lead to missing icons and a non functional WebIDE. An inspection of the html page shows, that some resources are requested over http://localhost/... which leads to 404 errors for those resources.

Since the GitLab container on Synology is not based on the omnibus package, you can not use directly external_url in /etc/gitlab/gitlab.rb. If you want to change the url you can do it by changing the docker environment parameter GITLAB_HOST.

GitLab on Synology: Environment settings

Setup GitLab Runner for Docker containers on Synology NAS

Posted by Mathias Lipowski
Docker / 6 Comments Tags: Docker, Git, GitLab, Synology

The setup described in this post has been tested on the following system:

DS216+II with 8GB RAM
DSM 6.2.3-25426 Update 2

In addition, the following software packages have already been installed on the system using the Synology package manager:

Docker 18.09.0-0513

GitLab is installed via the Docker Registry:

gitlab/gitlab-ce:latest (in my case GitLab 13.5.1-ce.0)

Install GitLab

You can skip this part, if GitLab is already running on your Synology and continue with the step Install GitLab Runner.

To install GitLab, open the Docker Registry and search for “gitlab”. Double click the entry gitlab/gitlab-ce:latest and select the latest version:

After the image is loaded, it will be listed under image. Launch this image and set the folders to be mounted as shown in the following image. This will simplify the access to the docker files within your Synology.

The port settings depend on your system. Normally, HTTP is accessible at port 80 or HTTPS on port 443. If your system already uses other apps that are running on those port, you can adjust them in Port Settings.

After completing the setup, it might take some time until the GitLab web surface is available. When accessing GitLab for the first time, you can specify a password for the root environment. The default username for the admin area is root. Now you can create user accounts, projects and perform any adjustments that fit your needs.

Install GitLab Runner

As the Synology DSM uses Docker to run GitLab, we can use Docker as well to install GitLab Runner. For this, connect to the Synology using SSH:

ssh <admin-user>@<synology> -p <port>

Now we can install the Gitlab Runner Docker container that can run other Docker containers to perform the runner tasks:

docker run -d \
--name gitlab_runner_docker \
--restart always \<br>--network host \
-v /run/docker.sock:/var/run/docker.sock \
gitlab/gitlab-runner:latest

This will install a Docker container with the name gitlab_runner_docker which uses the same network as Docker (‘–network host‘).

As this container is the basis for our Docker-in-Docker setup, we connect the Docker socket of our main container to the new one by using -v /run/docker.sock:/var/run/docker.sock.

You might also use the Docker GUI of DSM to create the container. But the step above can only be done with the help of the console command!

To test the container, you can use the following command to connect to the console:

docker exec -it gitlab_runner_docker /bin/bash

Register the runner

Now it’s time to register the runner:

docker exec -it gitlab_runner_docker gitlab-runner register

This will ask for some input:

Runtime platform                                    arch=amd64 os=linux pid=16 revision=e95f89a0 version=13.4.1
Running in system-mode.                            
                                                   
Please enter the gitlab-ci coordinator URL (e.g. https://gitlab.com/):
http://10.0.6.102:30000/
Please enter the gitlab-ci token for this runner:
ab1234abcd1234abcd12
Please enter the gitlab-ci description for this runner:
[synology]: docker_alpine
Please enter the gitlab-ci tags for this runner (comma separated):

Registering runner... succeeded                     runner=sA4DKorC
Please enter the executor: docker-ssh, parallels, docker+machine, kubernetes, docker, shell, ssh, virtualbox, docker-ssh+machine, custom:
docker
Please enter the default Docker image (e.g. ruby:2.6):
alpine:latest
Runner registered successfully. Feel free to start it, but if it's running already the config should be automatically reloaded!

In this case, the executor docker and the base image alpine:latest is used for this container.

If you use a self-signed certificate for GItLab, then you have to specify the certificate with the option --tls-ca-file during registration:

docker exec -it gitlab_runner_docker gitlab-runner register --tls-ca-file /path/to/fullchain.pem

Setup Docker-in-Docker

Let’s connect to the bash terminal of this container to change some settings:

docker exec -it gitlab_runner_docker /bin/bash

The created Docker container is an alpine base system without any packages installed. To perform the changes, we need a simple terminal text editor like nano or vim. The following commands will install nano for this task:

apt-get update
apt-get install nano

Now you can use nano to edit the GitLab Runner config file:

nano /etc/gitlab-runner/config.toml

And add the following lines as highlighted in the config file below:

clone_url = "http://10.0.6.102:30000/"
privileged = true
pull_policy = "if-not-present"

concurrent = 1
check_interval = 0

[session_server]
  session_timeout = 1800

[[runners]]
  name = "GitLab Runner Docker"
  url = "http://10.0.6.102:30000/"
  clone_url = "http://10.0.6.102:30000/"
  token = "Examp1eT0ken"
  executor = "docker"
  [runners.docker]
    tls_verify = false
    image = "node:latest"
    disable_entrypoint_overwrite = false
    oom_kill_disable = false
    disable_cache = false
    volumes = ["/cache"]
    shm_size = 0
    privileged = true
    pull_policy = "if-not-present"
  [runners.cache]
    [runners.cache.s3]
    [runners.cache.gcs]

That’s it. Now you can use this GitLab Runner for your repositories and run jobs by using other Docker containers.

Example usage in .gitlab-ci.yml

The following example uses a php container to run tests for a simple PHP application and deploy the code to a server. Some of the settings depend on the setup of your PHP application, so the example will not work out of the box. But it can give you a good idea of what is possible.

# https://hub.docker.com/_/php
image: php:7.4-fpm

services:
  - mysql:5.7

variables:
  # Configure mysql environment variables (https://hub.docker.com/_/mysql/)
  MYSQL_USER: $MYSQL_USER
  MYSQL_PASSWORD: $MYSQL_PASSWORD

before_script:
  # Initialize database, etc

stages:
  - test
  - deploy

test:
  stage: test
  script:
    - composer install
    - composer phpunit

deploy_production:
  stage: deploy
  environment:
    name: production
    url: https://www.example.com
  script:
    # run on server 'git checkout master && git pull origin master && exit'
  only:
    - master

Photo by sergio souza on Unsplash