Status

See also: SDK | Status

In Juju, status can describe the status of an application or a unit, where the former can be inferred from the latter and the latter consists of the workload and the Juju agent status. This document gives more information about all of these different kinds of status – their values and their meanings.

Contents:

Types of status

Application status

As its name indicates, the application status reports on the status of each deployed application.

The application status can be specified by the charm author. When not specified, it is the highest-priority status of the workload statuses of all of the application’s units. So if all workloads are active, the application will also be active, but if even just one workload is blocked, the application will also be marked blocked.

See more: Workload / charm status

The following figure provides an illustration of the status an application may be in at a given time, and lists the reasons for the transitions between different statuses:

Unit status

The unit status is given by the status of its workload/charm and the status of its juju agent.

A unit’s status is usually expressed as <workload status>/<agent status>, e.g. , active/idle or unknown/lost.

Workload / charm status

The workload / charm status reports the status of the charm(ed service):

Except for error, terminated and unknown, which are set by Juju, the workload status is generally speaking set by the charm. As such, its semantics is ultimately up to the charm author. The meanings listed below represent just the ideal case, if the charm author has followed the best practice guidelines.

Status Meaning
error The unit is in error, likely from a hook failure.
blocked The charm is stuck. Human attention/intervention is required.
maintenance The charm is performing some (long-running) task such as installing a package or restarting a service. Or, the charm is still being setup (installed) and has had no chance to set its own status yet.
waiting The charm is alive and well, and is waiting for some event to occur. No human intervention required.
active The charm is alive and well. Everything’s fine.
unknown The charm status is unknown. It may be still setting up, or something might have gone wrong.
terminated The workload is being destroyed, e.g. as a consequence of juju destroy-model.

Agent status

The agent status reports the status of the juju agent running in the unit as it interacts with the juju controller:

Status Meaning
allocating The charm pod has not come up yet.
idle The juju agent in the charm container is not doing anything at the moment, and waiting for events.
executing The juju agent in the charm container is executing some task.
error The juju agent in the charm container has run but has encountered an uncaught charm exception.
lost The juju agent is unresponsive, or its pod/container has unexpectedly come down.

The agent status is determined and set by the juju agent, so it cannot be directly controlled by the charm or a human operator.

Each newly deployed unit starts in maintenance/allocating, quickly going to maintenance/executing as the setup phase hooks are executed. If, by the time the install hook (if any) returns, the charm has set no workload status, the unit will go to unknown/idle. So, in principle, at the end of the install event handler it should be clear if all went well (in which case the user should set active) or not.

Status in the output of juju status

In the output of juju status, application status is given under App[lication] > Status and unit status – consisting, as we said, of the workload / charm status and of the Juju agent status – is given under Unit > Workload, Agent.


Expand to view a sample `juju status` output
Model        Controller           Cloud/Region        Version  SLA          Timestamp
charm-model  tutorial-controller  microk8s/localhost  3.1.5    unsupported  14:23:55+02:00

App             Version  Status  Scale  Charm           Channel    Rev  Address         Exposed  Message
demo-api-charm  1.0.0    active      1  demo-api-charm               0  10.152.183.175  no       
postgresql-k8s  14.7     active      1  postgresql-k8s  14/stable   73  10.152.183.237  no       Primary

Unit               Workload  Agent  Address      Ports  Message
demo-api-charm/0*  active    idle   10.1.157.72         
postgresql-k8s/0*  active    idle   10.1.157.74         Primary

See more: Command juju status

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