pingcap / pingcap/tidb-operator

TiDB operator hangs after setting the TiDB's `status.report-status` configuration to `false`

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Description

Bug Report

What version of Kubernetes are you using?
Client Version: v1.31.1
Kustomize Version: v5.4.2

What version of TiDB Operator are you using?
v1.6.0

What did you do?
We deployed a tidb cluster with 3 replicas of pd, tikv and tidb. After the cluster is initialized, we set the status.report-status to false in spec.tidb.config and applied the change.

After the TiDB operator successfully reconfigures the TiDB cluster, it loses the connectivity to the TiDB cluster, and it mistakenly thinks that the TiDB cluster is unhealthy and constantly tries to run failover. The failover spawns new pods, however, the operator still cannot contact the new pods.

The healthcheck fails at https://github.com/pingcap/tidb-operator/blob/24fa2832c4d1938e180b5baa6fde0450c38a8132/pkg/manager/member/tidb_member_manager.go#L303
which constantly triggers the Failover function.

How to reproduce

  1. Deploy a TiDB cluster with TiProxy enabled, for example:
apiVersion: pingcap.com/v1alpha1
kind: TidbCluster
metadata:
  name: test-cluster
spec:
  configUpdateStrategy: RollingUpdate
  enableDynamicConfiguration: true
  helper:
    image: alpine:3.16.0
  pd:
    baseImage: pingcap/pd
    config: "[dashboard]\n  internal-proxy = true\n"
    maxFailoverCount: 0
    mountClusterClientSecret: true
    replicas: 3
    requests:
      storage: 10Gi
  pvReclaimPolicy: Retain
  tidb:
    baseImage: pingcap/tidb
    config: '
      [performance]

      tcp-keep-alive = true
      '
    maxFailoverCount: 0
    replicas: 3
    service:
      externalTrafficPolicy: Local
      type: NodePort
  tikv:
    baseImage: pingcap/tikv
    config: 'log-level = "info"

      '
    maxFailoverCount: 0
    mountClusterClientSecret: true
    replicas: 3
    requests:
      storage: 100Gi
  timezone: UTC
  version: v8.1.0
  1. Add status.status-port to the spec.tidb.config
apiVersion: pingcap.com/v1alpha1
kind: TidbCluster
metadata:
  name: test-cluster
spec:
  configUpdateStrategy: RollingUpdate
  enableDynamicConfiguration: true
  helper:
    image: alpine:3.16.0
  pd:
    baseImage: pingcap/pd
    config: "[dashboard]\n  internal-proxy = true\n"
    maxFailoverCount: 0
    mountClusterClientSecret: true
    replicas: 3
    requests:
      storage: 10Gi
  pvReclaimPolicy: Retain
  tidb:
    baseImage: pingcap/tidb
    config: '
      [performance]

      tcp-keep-alive = true

      [status]

      report-status = false
      '
    maxFailoverCount: 0
    replicas: 3
    service:
      externalTrafficPolicy: Local
      type: NodePort
  tikv:
    baseImage: pingcap/tikv
    config: 'log-level = "info"

      '
    maxFailoverCount: 0
    mountClusterClientSecret: true
    replicas: 3
    requests:
      storage: 100Gi
  timezone: UTC
  version: v8.1.0

What did you expect to see?
We expected to see either the tidb restarts and new configuration takes effect or the tidb operator rejects the change since the operations of tidb operator depend on HTTP API service.

What did you see instead?
The last pod terminated and restarted. After that, tidb operator could not connect to the cluster and hanged.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start at pkg/manager/member/tidb_member_manager.go around line 303 and reproduce the change to spec.tidb.config that sets status.report-status to false in the provided Kubernetes manifest. Trace how the health check leads to Failover and new pod creation. Done means the operator either safely handles the configuration change and reconnects, or rejects it because its operations depend on the TiDB HTTP API.

Written by the indexing model from the issue text.

Assessment

Tech stack
go, kubernetes
Domain
infrastructure
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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