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influxdb 集群中,client 在 node1 上执行 remove metaNode node3 的命令:
influxd_ctl remove-meta node3:8091
整体流程如下:
- node1 收到 CLI 命令,向本人 8084 端口发送 GET /remove-meta 的申请,request body: {“metahttp:”: “node3:8091”};
- node1 向 node3 发送 GET http://node3:8091/ping,探测 node3 是否存活;
- node1 执行 metaclient.DeleteMetaNode():Raft 中删除该节点信息;
- node 向 node3 发送 GET http://node3:8091/remove-meta,node3 做一些清理操作;
CLI 命令解决
命令行代码入口:
// cmd/influxd_ctl/cli/cli.go
func (c *CommandLine) Run() error {
....
switch cmd {
case "remove-meta":
return do_remove_meta(c)
}
}
向本人的 8084 发送 GET /remove-meta:
func do_remove_meta(c *CommandLine) error {
// flag 读命令行的参数
fs := flag.NewFlagSet("", flag.ExitOnError)
o := RemoveMetaOptions{}
fs.BoolVar(&o.Force, "force", false, "force remove meta node")
fs.Parse(c.CMD[1:])
httpAddr := fs.Args()[len(fs.Args())-1]
force := "false"
if o.Force {force = "true"}
// 向本身的 8084 发送 remote-meta,body 中带要删除节点的 httpAddr
url := c.getURL("remove-meta", map[string]string{"metahttp": httpAddr, "force": force})
resp, err := http.Get(url)
if err != nil {return err}
defer resp.Body.Close()
.....
}
admin_cluster 监听 8084 端口,负责集群的治理性能,/remove-meta 的 handler:
// services/admin_cluster/handler.go
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case "GET":
switch r.URL.Path {
case "/remove-meta":
h.WrapHandler("remove-meta", h.removeMetaNode).ServeHTTP(w, r)
}
}
}
具体的解决:
- ping 一下 node3,看是否存活,若已不存活,则返回谬误;
- metaClient.DeleteMetaNode() 删除集群中该节点的信息;
- 向 node3 发送 /remove-meta;
func (h *handler) removeMetaNode(w http.ResponseWriter, r *http.Request) {ps := r.URL.Query()
var metahttp string
metahttp = ps["metahttp"][0]
var force bool
if len(ps["force"]) == 1 && ps["force"][0] == "true" {force = true}
metaLive := true
// 先 ping 一下看移除的节点否活着
// ping meta server first
url := "http://" + metahttp + "/ping"
resp, err := http.Get(url)
if err != nil {
metaLive = false
h.logger.Info("ping meta server failed", zap.Error(err))
}
if !force && !metaLive {h.sendResponse(fmt.Errorf("Meta node %s could not be connected", metahttp), w)
return
}
err = func() error {
// remove meta node and leave from raft cluster
nodeInfo := h.MetaClient.MetaNodeByAddr(metahttp)
if nodeInfo == nil {return fmt.Errorf("Meta node %s does not exist in cluster", metahttp)
}
// 删除该 meta 节点的元信息 (Raft)
if err := h.MetaClient.DeleteMetaNode(nodeInfo.ID); err != nil {return err}
// 向该节点的 8091 发送 remote-meta
// delete directory
url := "http://" + metahttp + "/remove-meta"
resp, err := http.Get(url)
if err != nil {return fmt.Errorf("Removed meta node from raft cluster, but remove meta data dir failed. %v", err)
}
body, err := ioutil.ReadAll(resp.Body)
return nil
}()
h.sendResponse(err, w)
}
node1 向 node3 发送 /ping
node1 发送 GET http://node3:8091/ping;
nod3 的解决:
//services/httpd/handler.go
// servePing returns a simple response to let the client know the server is running.
func (h *Handler) servePing(w http.ResponseWriter, r *http.Request) {atomic.AddInt64(&h.stats.PingRequests, 1)
h.writeHeader(w, http.StatusNoContent)
}
node1 删除 raft 中该节点信息
通过 metaClient.DeleteMetaNode() 删除集群中该节点的信息;
将删除节点命令封装成 1 个 Command_DeleteMetaNodeCommand,而后 retryUtilExec() 执行:
// services/meta/client.go
func (c *Client) DeleteMetaNode(id uint64) error {
cmd := &internal.DeleteMetaNodeCommand{ID: proto.Uint64(id),
}
return c.retryUntilExec(internal.Command_DeleteMetaNodeCommand, internal.E_DeleteMetaNodeCommand_Command, cmd)
}
retryUtilExec() 函数执行逻辑
- 向 metaServer 发送 POST /execute 执行 Command;
- 若该 metaServer 是 Follower,则将 command 转发给 Leader;
- 上述过程重试 10 次,直到胜利;
Leader 解决 POST /execute 申请,解决 DeleteMetaNodeCommand:
// services/meta/handler.go
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case "POST":
h.WrapHandler("execute", h.serveExec).ServeHTTP(w, r)
}
}
func (h *handler) serveExec(w http.ResponseWriter, r *http.Request) {
var resp *internal.Response
if err := h.store.apply(body); err != nil {
resp = &internal.Response{OK: proto.Bool(false),
Error: proto.String(err.Error()),
}
} else {
resp = &internal.Response{OK: proto.Bool(false),
Index: proto.Uint64(h.store.index()),
}
}
b, err := proto.Marshal(resp)
w.Header().Add("Content-Type", "application/octet-stream")
w.Write(b)
}
数据更新通过 store.apply() 执行:
func (fsm *storeFSM) Apply(l *raft.Log) interface{} {
var cmd internal.Command
if err := proto.Unmarshal(l.Data, &cmd); err != nil {panic(fmt.Errorf("cannot marshal command: %x", l.Data))
}
err := func() interface{} {switch cmd.GetType() {
case internal.Command_DeleteMetaNodeCommand:
return fsm.applyDeleteMetaNodeCommand(&cmd, s)
}
}()
...
}
具体到 fsm.applyDeleteMetaNodeComamnd():更新 fsm 中 metaNodes 的信息:
func (fsm *storeFSM) applyDeleteMetaNodeCommand(cmd *internal.Command, s *store) interface{} {ext, _ := proto.GetExtension(cmd, internal.E_DeleteMetaNodeCommand_Command)
v := ext.(*internal.DeleteMetaNodeCommand)
// 更新 other
other := fsm.data.Clone()
node := other.MetaNode(v.GetID())
if node == nil {return ErrNodeNotFound}
//node 来到
if err := s.leave(node); err != nil && err != raft.ErrNotLeader {return err}
if err := other.DeleteMetaNode(v.GetID()); err != nil {return err}
fsm.data = other
return nil
}
node1 向 node3 发送 /remove-meta
node3 接管 /remove-meta 做一些资源清理操作:
// services/meta/handler.go
func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case "GET":
switch r.URL.Path {
case "/remove-meta":
h.WrapHandler("remove-meta", h.serveRemoveMeta).ServeHTTP(w, r)
}
}
}
资源清理操作:
- 删除本机的 meta 目录;
- 新建本机的 meta 目录;
- 保留本机的节点信息 node.json 文件;
func (h *handler) serveRemoveMeta(w http.ResponseWriter, r *http.Request) {
// admin_cluster have removed meta node from data
// remove meta dir
err := func() error {
// 删除 meta 目录
// remove contents in meta dir except the node file
if err := os.RemoveAll(h.s.config.Dir); err != nil {return fmt.Errorf("remove meta dir failed: %v", err)
}
// 新建 meta 目录
if err := os.Mkdir(h.s.config.Dir, 755); err != nil {return fmt.Errorf("create empty meta dir failed: %v", err)
}
// 保留 node.json
// node file should be kept. Data node still needs it.
if err := h.s.Node.Save(); err != nil {return fmt.Errorf("save node file failed: %v", err)
}
return nil
}()
if err != nil {h.httpError(err, w, http.StatusInternalServerError)
} else {if _, err := w.Write([]byte("OK")); err != nil {h.logger.Info("Write response error", zap.Error(err))
}
}
}
正文完