Kubernetes——Debug Static Pod

news2024/11/23 21:28:41

1. 问题背景

注意，我这里的Static Pod并非Kubernetes的Static Pod，而是需要把想要Debug的程序放到Delve环境中重新打包一个镜像。因为还有另外一种场景，那就是我们需要不重启Running Pod，为了和这种方式区分，才以此为名。

最近遇到一个问题，简单说明一下背景。

由于虚拟机重新启动，造成Redis Operator无法组建Redis集群，报错为：[ERR] Node 10.233.75.71:6379 is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0。

这个错误比较典型，在网上一搜索就能找到解决方案。其实就是因为虚拟机重新启动之后，Pod被重建，IP发生变动，而nodes.conf文件由于被持久化，因此里面记录了上一次集群的信息。因此解决的方案也很简单，就是删除aof/rdb/nodes.conf文件。详细可以参考这篇文章：Operator——Redis之重启虚拟机后无法重建集群

为了让Redis Operator能够自动处理这种情况，我修改了Redis Operator的源码，如果在组件集群的时候发现是上面所说的错误，就自动删除aof/rdb/nodes.conf文件，重建集群

程序改完之后，发现Redis Operator一直卡在某个地方，实际上根据Redis Operator的源码可以知道，就算RedisCluster资源不发生改动，Redis Operator也会每隔10s重新Reconcile一遍。即便遇到错误返回，也会在120s之后，重新Reconcile

{"level":"info","ts":1671086466.020392,"logger":"controllers.RedisCluster","msg":"Will reconcile redis cluster operator in again 10 seconds","Request.Namespace":"redis-system","Request.Name":"redis"}
{"level":"info","ts":1671086476.0212002,"logger":"controllers.RedisCluster","msg":"Reconciling opstree redis Cluster controller","Request.Namespace":"redis-system","Request.Name":"redis"}
{"level":"info","ts":1671086476.0256453,"logger":"controller_redis","msg":"Redis statefulset get action was successful","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-leader"}
{"level":"info","ts":1671086476.0356286,"logger":"controller_redis","msg":"Reconciliation Complete, no Changes required.","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-leader"}
{"level":"info","ts":1671086476.0390885,"logger":"controller_redis","msg":"Redis service get action is successful","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-leader-headless"}
{"level":"info","ts":1671086476.0410442,"logger":"controller_redis","msg":"Redis service is already in-sync","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-leader-headless"}
{"level":"info","ts":1671086476.0445807,"logger":"controller_redis","msg":"Redis service get action is successful","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-leader"}
{"level":"info","ts":1671086476.0464318,"logger":"controller_redis","msg":"Redis service is already in-sync","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-leader"}
{"level":"info","ts":1671086476.0476692,"logger":"controller_redis","msg":"Redis PodDisruptionBudget get action failed","Request.PodDisruptionBudget.Namespace":"redis-system","Request.PodDisruptionBudget.Name":"redis-leader"}
{"level":"info","ts":1671086476.047689,"logger":"controller_redis","msg":"Reconciliation Successful, no PodDisruptionBudget Found.","Request.PodDisruptionBudget.Namespace":"redis-system","Request.PodDisruptionBudget.Name":"redis-leader"}
{"level":"info","ts":1671086476.0511396,"logger":"controller_redis","msg":"Redis statefulset get action was successful","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-leader"}
{"level":"info","ts":1671086476.05468,"logger":"controller_redis","msg":"Redis statefulset get action was successful","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-follower"}
{"level":"info","ts":1671086476.0869293,"logger":"controller_redis","msg":"Reconciliation Complete, no Changes required.","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-follower"}
{"level":"info","ts":1671086476.0903852,"logger":"controller_redis","msg":"Redis service get action is successful","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-follower-headless"}
{"level":"info","ts":1671086476.0920627,"logger":"controller_redis","msg":"Redis service is already in-sync","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-follower-headless"}
{"level":"info","ts":1671086476.0965445,"logger":"controller_redis","msg":"Redis service get action is successful","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-follower"}
{"level":"info","ts":1671086476.0986211,"logger":"controller_redis","msg":"Redis service is already in-sync","Request.Service.Namespace":"redis-system","Request.Service.Name":"redis-follower"}
{"level":"info","ts":1671086476.099773,"logger":"controller_redis","msg":"Redis PodDisruptionBudget get action failed","Request.PodDisruptionBudget.Namespace":"redis-system","Request.PodDisruptionBudget.Name":"redis-follower"}
{"level":"info","ts":1671086476.0997992,"logger":"controller_redis","msg":"Reconciliation Successful, no PodDisruptionBudget Found.","Request.PodDisruptionBudget.Namespace":"redis-system","Request.PodDisruptionBudget.Name":"redis-follower"}
{"level":"info","ts":1671086476.1040905,"logger":"controller_redis","msg":"Redis statefulset get action was successful","Request.StatefulSet.Namespace":"redis-system","Request.StatefulSet.Name":"redis-follower"}
{"level":"info","ts":1671086476.104127,"logger":"controllers.RedisCluster","msg":"Creating redis cluster by executing cluster creation commands","Request.Namespace":"redis-system","Request.Name":"redis","Leaders.Ready":"3","Followers.Ready":"3"}
{"level":"info","ts":1671086476.1103818,"logger":"controller_redis","msg":"Successfully got the ip for redis","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis-leader-0","ip":"10.233.74.86"}
{"level":"info","ts":1671086476.1114752,"logger":"controller_redis","msg":"Redis cluster nodes are listed","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Output":"cf0291a193357d03c6c2e6a67cf012689840affe 10.233.74.86:6379@16379 myself,master - 0 1671078114882 1 connected\n"}
{"level":"info","ts":1671086476.1115515,"logger":"controller_redis","msg":"Total number of redis nodes are","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Nodes":"1"}
{"level":"info","ts":1671086476.1184812,"logger":"controller_redis","msg":"Successfully got the ip for redis","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis-leader-0","ip":"10.233.74.86"}
{"level":"info","ts":1671086476.1197286,"logger":"controller_redis","msg":"Redis cluster nodes are listed","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Output":"cf0291a193357d03c6c2e6a67cf012689840affe 10.233.74.86:6379@16379 myself,master - 0 1671078114882 1 connected\n"}
{"level":"info","ts":1671086476.1197934,"logger":"controller_redis","msg":"Number of redis nodes are","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Nodes":"1","Type":"leader"}
{"level":"info","ts":1671086476.1198037,"logger":"controllers.RedisCluster","msg":"Not all leader are part of the cluster...","Request.Namespace":"redis-system","Request.Name":"redis","Leaders.Count":1,"Instance.Size":3}
{"level":"info","ts":1671086476.1235414,"logger":"controller_redis","msg":"Successfully got the ip for redis","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis-leader-0","ip":"10.233.74.86"}
{"level":"info","ts":1671086476.1272135,"logger":"controller_redis","msg":"Successfully got the ip for redis","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis-leader-1","ip":"10.233.97.165"}
{"level":"info","ts":1671086476.1303189,"logger":"controller_redis","msg":"Successfully got the ip for redis","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis-leader-2","ip":"10.233.75.68"}
{"level":"info","ts":1671086476.130354,"logger":"controller_redis","msg":"Redis Add Slots command for single node cluster is","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Command":["redis-cli","--cluster","create","10.233.74.86:6379","10.233.97.165:6379","10.233.75.68:6379","--cluster-yes"]}
{"level":"info","ts":1671086476.133076,"logger":"controller_redis","msg":"Redis cluster creation command is","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Command":["redis-cli","--cluster","create","10.233.74.86:6379","10.233.97.165:6379","10.233.75.68:6379","--cluster-yes","-a","T1XmQh9U"]}
{"level":"info","ts":1671086476.1361492,"logger":"controller_redis","msg":"Pod Counted successfully","Request.RedisManager.Namespace":"redis-system","Request.RedisManager.Name":"redis","Count":0,"Container Name":"redis-leader"}

root@lvs-229:~# date +'%Y-%m-%d %H:%M:%S' -d "@1671086476.1361492"
2022-12-15 14:41:16
root@lvs-229:~#

可以看到，程序最后一次输出的日志为20分钟以前，非常的诡异。程序停留在了Pod Counted successfully附近，而我排查了一下源代码，并没有发现阻塞的地方。那么是什么原因导致程序开启了是”卡住“呢？由于redis集群组件的特性，我本地的windows10电脑无法复现，需要在K8S集群只能，Redis Operator才能跑起来。所以我需要能够在K8S Pod内Debug我修改之后的Redis Operator程序。

2. 编译源码

由于需要Debug源码，而golang编译器默认开启了内联优化，因此我们需要在编译二进制的时候，关闭内联优化

go build -gcflags=all="-N -l" -o manager ./cmd/operator/main.go

如上，通过加入-N -l选项，就可以禁止内联优化

3. Dockerfile

可以Debug的二进制程序准备好了，下面我们就可以准备Dockerfile，上传镜像了，需要注意的是，我们需要在启动的时候通过delve来启动，才能让我们的IDEA连接到Pod当中

FROM golang:1.19.4

MAINTAINER skyguard-bigdata
WORKDIR /
USER root
COPY manager .
RUN chmod +x /manager

RUN go env -w GO111MODULE=on && \
    go env -w GOPROXY=https://goproxy.cn,direct && \
    go install github.com/go-delve/delve/cmd/dlv@latest

EXPOSE 12345

CMD dlv --listen=:12345 --headless=true --api-version=2 --accept-multiclient exec manager -- --leader-elect

构建镜像，如下：

[root@9a394601b73f redis-operator]# docker build -t redis-operator:0.13.2-debug -f Dockerfile-Debug .
Sending build context to Docker daemon  188.4MB
Step 1/9 : FROM golang:1.19.4
 ---> 180567aa84db
Step 2/9 : MAINTAINER skyguard-bigdata
 ---> Using cache
 ---> 5750b24ad20d
Step 3/9 : WORKDIR /
 ---> Using cache
 ---> 1c31e39cec1d
Step 4/9 : USER root
 ---> Using cache
 ---> a059bffdeaf7
Step 5/9 : COPY manager .
 ---> Using cache
 ---> fec9465515d8
Step 6/9 : RUN chmod +x /manager
 ---> Using cache
 ---> 19e9cabec7f7
Step 7/9 : RUN go env -w GO111MODULE=on &&     go env -w GOPROXY=https://goproxy.cn,direct &&     go install github.com/go-delve/delve/cmd/dlv@latest
 ---> Running in 5dfa25abd876
go: downloading github.com/go-delve/delve v1.20.1
go: downloading github.com/sirupsen/logrus v1.6.0
go: downloading github.com/spf13/cobra v1.1.3
go: downloading gopkg.in/yaml.v2 v2.4.0
go: downloading github.com/mattn/go-isatty v0.0.3
go: downloading github.com/cosiner/argv v0.1.0
go: downloading github.com/derekparker/trie v0.0.0-20200317170641-1fdf38b7b0e9
go: downloading github.com/go-delve/liner v1.2.3-0.20220127212407-d32d89dd2a5d
go: downloading github.com/google/go-dap v0.6.0
go: downloading go.starlark.net v0.0.0-20220816155156-cfacd8902214
go: downloading golang.org/x/sys v0.0.0-20220908164124-27713097b956
go: downloading github.com/hashicorp/golang-lru v0.5.4
go: downloading golang.org/x/arch v0.0.0-20190927153633-4e8777c89be4
go: downloading github.com/cpuguy83/go-md2man/v2 v2.0.0
go: downloading github.com/spf13/pflag v1.0.5
go: downloading github.com/mattn/go-runewidth v0.0.13
go: downloading github.com/cilium/ebpf v0.7.0
go: downloading github.com/russross/blackfriday/v2 v2.0.1
go: downloading github.com/rivo/uniseg v0.2.0
go: downloading github.com/shurcooL/sanitized_anchor_name v1.0.0
Removing intermediate container 5dfa25abd876
 ---> 0397bab71dd9
Step 8/9 : EXPOSE 12345
 ---> Running in 3e585f70d0a6
Removing intermediate container 3e585f70d0a6
 ---> 3dd708e29767
Step 9/9 : CMD dlv --listen=:12345 --headless=true --api-version=2 --accept-multiclient exec manager
 ---> Running in 0d8181e63ea7
Removing intermediate container 0d8181e63ea7
 ---> 77f30b173d34
Successfully built 77f30b173d34
Successfully tagged redis-operator:0.13.2-debug
[root@9a394601b73f redis-operator]# docker images
REPOSITORY                          TAG              IMAGE ID       CREATED          SIZE
redis-operator                      0.13.2-debug     77f30b173d34   10 seconds ago   1.21GB

把镜像推送到仓库当中即可

4. Service

由于之前的Redis Operator并不需要提供服务，因此并没有Service，这里我们需要把12345端口暴露出来

注意：如果小伙伴们可以直接访问K8S集群的话，那么这里可以直接使用NodePort的方式暴露端口，并且Apisix那个步骤可以跳过

kind: Service
apiVersion: v1
metadata:
  name: redis-operator-debug
  namespace: redis-system
spec:
  type: ClusterIP
  ports:
    - name: delve
      port: 12345
      targetPort: 12345
  selector:
    control-plane: redis-operator

root@lvs-229:~# kubectl get svc -n redis-system
NAME                      TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)             AGE
redis-follower            ClusterIP   10.233.5.220   <none>        6379/TCP,9121/TCP   28h
redis-follower-headless   ClusterIP   None           <none>        6379/TCP            28h
redis-leader              ClusterIP   10.233.0.234   <none>        6379/TCP,9121/TCP   28h
redis-leader-headless     ClusterIP   None           <none>        6379/TCP            28h
redis-operator-debug      ClusterIP   10.233.19.68   <none>        12345/TCP           19s
root@lvs-229:~#

5. Apisix

由于我们的K8S是通过Apisix网关暴露给外部的，因此这里还需要给Apisix添加一个四层代理，这样外部才能的delve才能连接上K8S内部的Pod

PUT {{ApisixManagerAddr}}/apisix/admin/stream_routes/redis-operator-debug
Content-Type: {{ContentType}}
X-API-KEY: {{ApisixKey}}

{
  "server_port": 9107,
  "upstream": {
    "type": "roundrobin",
    "nodes": {
      "10.233.19.68:12345": 1
    }
  }
}

由于集群内的DNS解析暂时有点问题，这里我们通过Service IP找到服务

6. Deployment

修改Redis Operator的Image属性，改为我们前面上传的镜像并且加上特权，privileged: true。

切记，这里一定要记得给容器加上特权，否则Debug会有问题

securityContext:
  privileged: true

root@lvs-229:~# kubectl logs -f --tail 100 -n redis-system redis-operator-546fdc76b7-lqz9b
2022-12-15T08:23:44Z error layer=debugger could not create config directory: mkdir .config: permission denied
2022-12-15T08:23:44Z warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)
API server listening at: [::]:12345

更新Deployment之后，等待Kubernetes重启好新的Pod，查看日志，发现这个Pod正在等待delve连接进来，接下来，我们启动IDEA

7. IDEA

注意：需要提前打好端点，不然IEDA已启动，很有可能我们需要Debug的地方已经跳过了

在这里插入图片描述

搞定，之后就可以愉快的Debug啦

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