Getting the lock status with invoke passes through any options from the
original command which will raise an exception if they are not also
valid for the lock status command.
Fixes https://github.com/mrsked/mrsk/issues/239
Rather than waiting 5 seconds and hoping for the best after we boot
docker compose, add docker healthchecks and wait for all the containers
to be healthy.
Adds a simple integration test to ensure that `mrsk deploy` works.
Everything required is spun up with docker compose:
- shared: a container that contains an ssh key and a self signed cert to
be shared between the images
- deployer: the image we will deploy from
- registry: a docker registry
- two vm images to deploy into
- load_balancer: an nginx load balancer to use between our images
The other images are in privileged mode so that we can run
docker-in-docker. We need to run docker inside the images - mapping in
the docker socket doesn't work because both VMs would share the host
daemon.
The docker registry requires a self signed cert as you cannot use basic
auth over HTTP except on localhost. It runs on port 4443 rather than 443
because docker refused to accept that "registry" is a docker host and
tries to push images to docker.io/registry. "registry:4443" works fine.
The shared container contains the ssh keys for the deployer and vms, and
the self signed cert for the registry. When the shared container boots,
it copies them into a shared volume.
The other deployer and vm images are built with soft links from the
shared volume to the require locations. Their boot scripts wait for the
files to be copied in before continuing.
The root mrsk folder is mapped into the deployer container. On boot it
builds the gem and installs it.
Right now there's just a single test. We confirm that the load balancer
is returning a 502, run `mrsk deploy` and then confirm it returns 200.
Replaces our current host-based HTTP healthchecks with Docker
healthchecks, and adds a new `healthcheck.cmd` config option that can be
used to define a custom health check command. Also removes Traefik's
healthchecks, since they are no longer necessary.
When deploying a container that has a healthcheck defined, we wait for
it to report a healthy status before stopping the old container that it
replaces. Containers that don't have a healthcheck defined continue to
wait for `MRSK.config.readiness_delay`.
There are some pros and cons to using Docker healthchecks rather than
checking from the host. The main advantages are:
- Supports non-HTTP checks, and app-specific check scripts provided by a
container.
- When booting a container, allows MRSK to wait for a container to be
healthy before shutting down the old container it replaces. This
should be safer than relying on a timeout.
- Containers with healthchecks won't be active in Traefik until they
reach a healthy state, which prevents any traffic from being routed to
them before they are ready.
The main _disadvantage_ is that containers are now required to provide
some way to check their health. Our default check assumes that `curl` is
available in the container which, while common, won't always be the
case.
If we get an error we'll only hold the deploy lock if it occurs while
trying to switch the running containers.
We'll also move tagging the latest image from when the image is pulled
to just before the container switch. This ensures that earlier errors
don't leave the hosts with an updated latest tag while still running the
older version.
* main: (24 commits)
Bump version for 0.11.0
Labels can be added to Traefik
Make rollbacks role-aware
fix typo role to roles
Explained the latest modifications of Traefik container labels
Remove .idea folder
Updated README.md with new healthcheck.max_attempts option
Fix test case: console output message was not updated to display the current/total attempts
Require net-ssh ~> 7.0 for SHA-2 support
Improved deploy lock acquisition
Excess CR
Style
Simpler
Make it explicit, focus on Ubuntu
More explicit
Not that --bundle is a Rails 7+ option
Update README.md
Update README.md
Improved: configurable max_attempts for healthcheck
Traefik service name to be derived from role and destination
...
Rollbacks stopped working after https://github.com/mrsked/mrsk/pull/99.
We'll confirm that a container is available for the first role on the
primary host before attempting to rollback.
Donal McBreen