UCP: Support the noise reduction for auto-scaling

[Yisaer]

Description

Currently, the auto-scaling doesn't have the noise reduction design. It means in each reconciliation in auto-scaling controller, the result would be updated into tidbcluster immediately when the result indicates to scale-out or scale-in.

Now we want to support the noise reduction for auto-scaling and design detailed is designed in following:

For TidbClusterAutoScaler, the status would have 3 choices: Normal / ReadyToScaleOut / ReadyToScaleIn.

1. The initialial status is Normal
2. If the result in the reconciliation in auto-scaling controller is lager/smaller than the current replicas, the status would become ReadyToScaleOut/ReadyToScaleIn and record the timestamp in annotation.
3. If the status is remained as ReadyToScaleOut / ReadyToScaleIn for a certain time (which could also be configured in the TidbClusterAutoScaler spec), the auto-scaling controller would finally updated its result in the tidbcluster.
4. When auto-scaling updated the tidbcluster or the result in the reconciliation in auto-scaling controller is equal to the current replicas, the status should become Normal again.

I think the PR for this issue not only contains the logic of the noise reduction but also should have a e2e case to cover it. You could look the previous logic for auto-scaling in e2e here:

tidb-operator/tests/e2e/tidbcluster/serial.go

Line 653 in 5341bab

ginkgo.It("auto-scaling TidbCluster", func() {

Score

• 2500

Mentor(s)

• @yisaer

Contact the mentors: #tidb-challenge-program channel in TiDB-Operator Community Slack Workspace
As the logic is not simple and the detail is still needed to be discussed, we are welcome for every challenger to contact the mentor if you have any questions.

Recommended Skills

• Golang
• Kubernetes

[TennyZhuang]

/pick-up-challenge

[sre-bot]

@TennyZhuang already had picked pingcap/tidb-dashboard#303, pingcap/tidb#15008, tikv/tikv#7223, finish one before pick up a new one.

[zhoudian64]

/pick-up-challenge

[sre-bot]

@zhoudian64 don't have enough score, pick up failed

Progress 0/200
You may pick up some easy issues first

[vincent178]

/pick-up-challenge

[sre-bot]

@vincent178 pick up issue success

[Yisaer]

@vincent178 Hi, Is there any progress now?

[vincent178]

@Yisaer yeah, I'm still reading the code, will reach out to you maybe tomorrow or the day after to discuss some details, thanks.

[Yisaer]

@vincent178 okay, please contact me through slack personal message if you have any problem or question. I would help you.