I have two containers，maybe A and B, which A should run before B, but A is a server application, which the final type is Running but not Complete, so I wonder in this way, will B be never executed? So how can I deal with it?
If A and B are part of the same pod, then initContainer is the legacy way to establish ordering.
From the Kubernetes Pod lifecycle, I suppose you mean "Running, but no Terminated"
A pod liveness/readiness probe is in your case a better fit, since the server will not accept request until ready.
Read "Straight to the Point: Kubernetes Probes" from Peter Malina
Both readiness and liveness probe run in parallel throughout the life of a container.
- Use the liveness probe to detect an internal failure and restart the container (e.g. HTTP server down).
- Use the readiness probe to detect if you can serve traffic (e.g. established DB connection) and wait (not restart) for the container.
A dead container is also not a ready container.
To serve traffic, all containers within a pod must be ready.
You can add a pod readiness gate (stable from 1.14) to specify additional conditions to be evaluated for Pod readiness.
Read also "Kubernetes Liveness and Readiness Probes: How to Avoid Shooting Yourself in the Foot" from Colin Breck
"Should Health Checks call other App Health Checks" compares that approach with the InitContainer approach