A deployment group is a set of hosts with configuration and state on the masters that helps you deploy Helios jobs to agents more easily. It determines the list and sequence of hosts to deploy, undeploys prior jobs it has deployed, and deploys the specified job.
See the original proposal here for background and motivation.
A host selector is an expression of the form [label] [operator] [operand]. Host selectors are used by deployment groups to choose which hosts to act on. The command below will create a deployment group whose hosts match all the specified host selectors.
$ helios create-deployment-group foo-group foo=bar baz=qux
Creating deployment group: {"labels":{"baz":"qux","foo":"bar"},"name":"foo-group"}
{"status":"CREATED"}
Here's a list of the available types of host selectors:
- [label] = foo
- [label] != foo
- [label] in (foo, bar, qux, ...)
- [label] notin (foo, bar, qux, ...)
Creating a deployment group with the same name and labels as an existing one will succeed with a "not modified" response. Creating a deployment group with the same name but different labels as an existing one will return an error stating that the deployment group already exists.
Use helios hosts
to see what labels hosts have.
To change the definition of a deployment group, such as adding/removing host
selectors, you will need to remove the group, create it again with the same
name and new host selectors, and then run rolling-update --migrate
again.
Inspect the deployment group:
$ helios inspect-deployment-group foo-group
Name: foo-group
Labels: baz=qux
foo=bar
Job:
List deployment groups:
$ helios list-deployment-groups
foo-group
Tell the deployment group to deploy job foo:0.1.0 to all its agents.
$ helios rolling-update foo:0.1.0 foo-group
Rolling update started: foo-group -> foo:0.1.0 (parallelism=1, timeout=300)
host1 -> RUNNING (1/3)
host2 -> RUNNING (2/3)
host3 -> RUNNING (3/3)
Done.
Duration: 4.00 s
This command makes a deployment request and blocks until the update is complete. Helios determines the list and sequence of agents, undeploys any prior jobs this deployment group had deployed, and deploys the new job. If the job fails to reach the RUNNING state on any agent, the rolling update is stopped and marked as FAILED.
If the update succeeds it is marked as ACTIVE. Helios will periodically recalculate the list of agents that match the deployment group labels and make sure they are all running the specified job. This means new agents that match the labels will automatically be told to deploy the job.
See more rolling-update options with helios rolling-update -h
, e.g. parallel deployments and failure timeouts.
If you add --overlap
, the rolling-update
will, for every host, first deploy the new version of
a job before undeploying the old one. Note that the command will fail if the job contains static
port assignments.
Check on the status:
$ helios deployment-group-status foo-group
Name: foo-group
Job Id: foo-job:0.1.0
Status: ROLLING_OUT
HOST UP-TO-DATE JOB STATE
host1. X foo-job:0.1.0 RUNNING
host2. X foo-job:0.1.0 PULLING_IMAGE
host3. - -
See more deployment group commands with helios -h
.