Last updated: 20 Nov 2024

govuk-docker: Troubleshooting

`bin/setup` fails to succeed

If bin/setup fails on installing dnsmasq, make sure you're not overriding the USER env variable anywhere.

Diagnose common issues when setting up GOV.UK Docker

Run the following command in ~/govuk/govuk-docker.

bin/doctor

Since this script makes use of Ruby Gems, you will need to install some additional dependencies in order to do this.

First make sure you have the following dependencies:

rbenv

Next install Ruby / dependencies and run all the tests:

rbenv install

bundle install

Diagnose database issues with a project/app not making

If you run make on an app inside govuk-docker and face any of the following database issues:

ActiveRecord::Migration is not supported
duplicate key error

...then it is likely that there is a conflict between the app and one of your existing volumes. This is because database contents are stored in a volume that the container uses, so when the container is recreated, it picks up the same data again.

The easiest resolution is to drop the database, e.g. govuk-docker run content-store-lite bundle exec rails db:mongoid:drop, and then try to make again.

A blunter solution would be to drop the volume altogether, by running docker volume rm VOLUME_NAME, where VOLUME_NAME can be derived from docker volume ls.

Diagnose general issues with a project/app not working

Make sure you run all commands via GOV.UK Docker.

govuk-docker-run bundle install
govuk-docker-run rake db:migrate

Try repeating the action. If you got a GdsApi::HTTPUnavailable or GdsApi::TimedOutException the first time around, it could mean that Publishing API wasn't ready in time, as unfortunately there's no way for govuk-docker to know when each dependency is ready.
Check if one of the dependencies is the problem.

A common problem for dependencies is when you've previously git pulled the repo, but haven't run bundle install or rake db:migrate. The logs for the dependency will show if this is the problem.

# check if any dependencies have exited
docker ps -a

# check logs for an exited dependency
govuk-docker logs -f publishing-api-app

Try cleaning up and running your command again.

# stop all apps and their dependencies
govuk-docker down

# make sure GOV.UK Docker is up-to-date
git pull

Diagnose issues with `dev.gov.uk` domains not resolving

Check if domain runs on HTTP

Chrome browser redirects the domain to HTTPS, which doesn't load the page. You can disable this setting on your browser, test the domain on a private window or use another browser.

Check if dev.gov.uk works end-to-end

dig app.dev.gov.uk @127.0.0.1

# output should contain...
# app.dev.gov.uk.		0	IN	A	127.0.0.1

Check your /etc/resolver config is working

scutil --dns

# output should contain...
# domain   : dev.gov.uk
# nameserver[0] : 127.0.0.1
# port     : 53
# flags    : Request A records, Request AAAA records
# reach    : 0x00030002 (Reachable,Local Address,Directly Reachable Address)

Re-run the setup script and look for errors

bin/setup

Resolve issues caused by an existing Docker installation

You may get one of the following errors when running bin/setup.

Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink bin/docker-compose
Target /usr/local/bin/docker-compose
...

Error: It seems there is already an App at '/Applications/Docker.app'.

This isn't a problem if you already have Docker/Compose installed, and the setup script will continue to run. If you like, you can remove your existing Docker/Compose and run bin/setup again.

Cannot `rails db:prepare` or start console due to "Plugin caching_sha2_password could not be loaded"

In MySQL 8.0 caching_sha2_password was made the default over the previous mysql_native_password.

This can lead to the following error when ActiveRecord is attempting to connect to the database, for example when running rails db:prepare or trying to bring up a rails console.

ActiveRecord::ConnectionNotEstablished: Plugin caching_sha2_password could not be loaded: /usr/lib/x86_64-linux-gnu/mariadb19/plugin/caching_sha2_password.so: cannot open shared object file: No such file or directory

A workaround is to get MySQL to fall back to using mysql_native_password as follows:

Check that you can see govuk-docker-mysql-8-1 when running govuk-docker ps, if not you will need to start a service that uses mysql (for example Whitehall).
Bring up a mysql console inside the container: docker exec -it govuk-docker-mysql-8-1 mysql --user=root --password=root
Alter the way the root user identifies itself. ALTER USER 'root' IDENTIFIED WITH mysql_native_password BY 'root';

Browser based tests fail with `NoSuchSessionError: invalid session id`

For example: Jasmine unit tests or feature specs that use Capybara

Docker allocates 64mb shared memory to containers by default, but recent versions of Chrome require more than this. Otherwise you'll start to see error messages complaining about an "invalid session id". In a previous discussion on Slack, it was informally agreed that 512mb seems to be the 'right sized' amount to allocate – but this was anecdotal, so other values may work equally well for our needs.

If the shm_size is too small, you'll get error messages that look something like this in your terminal:

NoSuchSessionError: invalid session id
    at Object.throwDecodedError (/govuk/whitehall/node_modules/selenium-webdriver/lib/error.js:522:15)
    at parseHttpResponse (/govuk/whitehall/node_modules/selenium-webdriver/lib/http.js:548:13)
    at Executor.execute (/govuk/whitehall/node_modules/selenium-webdriver/lib/http.js:474:28)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)
    at async thenableWebDriverProxy.execute (/govuk/whitehall/node_modules/selenium-webdriver/lib/webdriver.js:735:17)
    at async Object.runSpecs (/govuk/whitehall/node_modules/jasmine-browser-runner/index.js:116:9)
    at async Command.runSpecs (/govuk/whitehall/node_modules/jasmine-browser-runner/lib/command.js:187:5) {
  remoteStacktrace: '#0 0xaaaabaf6b1b0 <unknown>\n' +
    '#1 0xaaaabada13b0 <unknown>\n' +
    '#2 0xaaaabadc7fe4 <unknown>\n' +
    '#3 0xaaaabadc9864 <unknown>\n' +
    '#4 0xaaaabafa75f8 <unknown>\n' +
    '#5 0xaaaabafa9d98 <unknown>\n' +
    '#6 0xaaaabafa9acc <unknown>\n' +
    '#7 0xaaaabaf987e0 <unknown>\n' +
    '#8 0xaaaabafaa500 <unknown>\n' +
    '#9 0xaaaabaf8e080 <unknown>\n' +
    '#10 0xaaaabafc1790 <unknown>\n' +
    '#11 0xaaaabafc1950 <unknown>\n' +
    '#12 0xaaaabafdbbd4 <unknown>\n' +
    '#13 0xffffb0f28628 <unknown>\n' +
    '#14 0xffffb075501c <unknown>\n'
}
error Command failed with exit code 1.

To resolve it, check your project's docker-compose.yml file. The *-lite service will need a shm_size config to be added.

For example:

services:
  whitehall-lite:
    <<: *whitehall
    shm_size: 512mb
    depends_on:
      - mysql-8
      - redis
    # ...

For further examples, see the PR alphagov/govuk-docker#613.

Resolve issue with a project/app not making

You may get this error when running make <app-name>.

 => ERROR [ 2/11] RUN apt-get update -qq && apt-get install -y chromium chromium-driverq
...
executor failed running [/bin/sh -c apt-get update -qq && apt-get install -y chromium chromium-driver]: exit code: 100

This may resolve by removing orphan containers which were created in a previous run of docker-compose up, but which has since been deleted from the docker-compose.yml file

docker-compose down -v --rmi all --remove-orphans

Rails database schema changed unexpectedly when running `rake db:migrate`

It is common to find that running rake db:migrate results in unexpected changes to the schema.rb file. This is caused by slight differences between databases running in GOV.UK Docker and the production databases on AWS.

Unfortunately, to resolve the issue, the only solution is to drop the database in GOV.UK docker and create a new one.

Once you have taken a backup, you can remove and re-create your local database using the following commands:

rake db:drop
rake db:create
rake db:schema:load
rake db:schema:migrate // optional, but if you are adding a new migration this will now update the schema without creating a horrible diff

govuk-docker: Troubleshooting

bin/setup fails to succeed