Add health checker #119
Add health checker #119
Conversation
Signed-off-by: Maksym Pavlenko <makpav@amazon.com>
machine.go
Outdated
| @@ -707,6 +707,13 @@ func (m *Machine) UpdateGuestDrive(ctx context.Context, driveID, pathOnHost stri | |||
| return nil | |||
| } | |||
|
|
|||
| // IsAlive makes sure that a Firecracker instance is running and responds via API by | |||
| // calling `DescribeInstance` endpoint behind. | |||
| func (m *Machine) IsAlive(ctx context.Context) error { | |||
There was a problem hiding this comment.
It looks like one of the valid states that can be returned by DescribeInstance is Halted: https://github.com/firecracker-microvm/firecracker/blob/35b73437641122865b1603bd74c144035e1790c9/api_server/swagger/firecracker.yaml#L453
There's also Uninitialized. That makes me feel like IsAlive is not really what one would expect. It seems more like it's checking whether the VM manager is alive rather than what we'd consider the Machine.
If we want to keep the behavior as is, I can't think of any great names, but maybe something like Exists would be better than IsAlive?
On the other hand, would it make sense to change the behavior and return an error here if the State is Halted or Uninitialized? What's the actual motivation behind this change?
There was a problem hiding this comment.
(I accidentally clicked the approve button, I think this should be addressed before merging)
There was a problem hiding this comment.
(@sipsma - I've "dismissed" your review per your comment here.)
There was a problem hiding this comment.
Some suggestions for names: IsVMMAlive, IsVMMResponsive, Reachable
samuelkarp
dismissed
sipsma’s stale review
"I accidentally clicked the approve button, I think this should be addressed before merging" - @sipsma
Signed-off-by: Maksym Pavlenko <makpav@amazon.com>
| return err | ||
| } | ||
|
|
||
| state := StringValue(instance.Payload.State) |
There was a problem hiding this comment.
I don't think it makes sense to verify the state if the purpose of this method is to see whether Firecracker responds to an API. I think getting any non-error response would meet the success criteria.
There was a problem hiding this comment.
If the motivation behind the change is to test the responsiveness of the API, then agreed and also think IsVMMResponsive is a good name.
If the motivation is instead to test that the Machine is in the running state, then can we just add a State function that returns the state value, whatever it may be?
There was a problem hiding this comment.
@haikuoliu which behavior would suite better here?
There was a problem hiding this comment.
Right now I've renamed it to IsRunning which tells whether a VM is in Starting or Running state.
There was a problem hiding this comment.
It is a bit confusing to see that we have Running as a state, and IsRunning actually means IsRunningOrStarting. Naming is hard...
I'm inclined to expose Firecracker's state as is instead of introducing our own notion of the state (running, responsive, alive, ...).
There was a problem hiding this comment.
The status type could provide rich methods later, like https://godoc.org/inet.af/http#Status.IsClientError (inet.af is bradfitz's net/http rework proposal, which is referenced from golang/go#29652)
Signed-off-by: Maksym Pavlenko <makpav@amazon.com>
|
Closing until we figure out requirements. |
Signed-off-by: Maksym Pavlenko makpav@amazon.com
Issue #, if available:
#115
Description of changes:
Adds
IsAliveBy submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.