Consul 入門實戰(2)--安裝及管理

本文主要介紹 Consul 的安裝及使用，文中使用到的軟件版本：RHEL 6.6、Consul 1.11.1。

1、單機版安裝

1.1、下載 Consul 並解壓

https://www.consul.io/downloads

unzip consul_1.11.1_linux_amd64.zip

1.2、啟動

./consul agent -server -ui -bootstrap-expect=1 -data-dir=./data -datacenter=dc1 -node=node10 -client=0.0.0.0 -bind=10.49.196.10

參數說明：

-server： 以 server 身份啟動；不加該參數默認是 client
-ui：可以訪問 UI 界面
-bootstrap-expect：集群期望的節點數，只有節點數量達到這個值才會選舉 leader
-data-dir：數據存放的目錄
-datacenter：數據中心名稱，默認是 dc1
-node：節點的名稱
-client：客戶端訪問 Consul 的綁定地址；默認為 127.0.0.1，只能本地訪問
-bind：集群內部通信綁定的地址，默認為 0.0.0.0

1.3、控制台

http://10.49.196.10:8500/

2、集群安裝

2.1、規划

機器	agent 類型	數據中心名稱
10.49.196.10	server	dc1
10.49.196.11	server	dc1
10.49.196.12	server	dc1

2.2、啟動

這里通過配置文件來依次啟動各節點(先啟動 10.49.196.10，再啟動其他兩個節點)：

nohup ./consul agent -config-file=./agent.hcl &

10.49.196.10 上 agent.hcl:

server = true,
ui_config = {
  enabled = true
},
bootstrap_expect = 3,
data_dir = "./data",
datacenter = "dc1",
node_name = "node10",
client_addr = "0.0.0.0",
bind_addr = "10.49.196.10"

10.49.196.11 上 agent.hcl:

server = true,
ui_config = {
  enabled = true
},
bootstrap_expect = 3,
data_dir = "./data",
datacenter = "dc1",
node_name = "node11",
client_addr = "0.0.0.0",
bind_addr = "10.49.196.11"
start_join = ["10.49.196.10"],
retry_join = ["10.49.196.10"],

10.49.196.12 上 agent.hcl:

server = true,
ui_config = {
  enabled = true
},
bootstrap_expect = 3,
data_dir = "./data",
datacenter = "dc1",
node_name = "node12",
client_addr = "0.0.0.0",
bind_addr = "10.49.196.12"
start_join = ["10.49.196.10"],
retry_join = ["10.49.196.10"],

 配置文件中參數說明：

server：同命令行的 server 參數
bootstrap_expect：同命令行的 bootstrap-expect 參數
data_dir：同命令行的 data-dir 參數
datacenter：同命令行的 datacenter 參數
node_name：同命令行的 node 參數
client_addr：同命令行的 client 參數
bind_addr：同命令行的 bind 參數
start_join：啟動時加入集群的地址，同命令行的 join 參數
retry_join：加入集群的重試地址，同命令行的 retry-join 參數

2.3、管理

2.3.1、查看節點信息

./consul members

結果如下：

Node     Address             Status  Type    Build   Protocol  DC   Partition  Segment
node10   10.49.196.10:8301   alive   server  1.11.1  2         dc1  default    <all>
node11   10.49.196.11:8301   alive   server  1.11.1  2         dc1  default    <all>
node12   10.49.196.12:8301   alive   server  1.11.1  2         dc1  default    <all>

2.3.2、查看集群狀態

./consul operator raft list-peers

結果如下：

Node     ID                                    Address             State     Voter  RaftProtocol
node10   e8974195-0bfc-9156-c4ea-abb2b594f75e  10.49.196.10:8300   leader    true   3
node11   bf0f6378-fb29-8fad-07f3-2d369a8093c3  10.49.196.11:8300   follower  true   3
node12   d460dfcd-607b-2804-725e-28aa79566127  10.49.196.12:8300   follower  true   3

2.3.3、退出集群

A、優雅的離開集群並關閉

./consul leave [-http-addr=<address>]

執行該命令后，該節點的狀態變為 “left”；參數 http-addr 默認為 http://127.0.0.1:8500，即本機所在節點。在 10.49.196.12 上執行該命令后，再查看節點信息如下：

Node     Address             Status  Type    Build   Protocol  DC   Partition  Segment
node10   10.49.196.10:8301   alive   server  1.11.1  2         dc1  default    <all>
node11   10.49.196.11:8301   alive   server  1.11.1  2         dc1  default    <all>
node12   10.49.196.12:8301   left    server  1.11.1  2         dc1  default    <all>

B、強制設置節點狀態為 “left”

./consul force-leave [-prune] nodeName

如果節點狀態為 “alive”，該節點會重新加入集群，所以看起來命令沒啥效果。

對於 ”fail" 或 “left” 狀態的節點，可以通過該命令把節點從集群中徹底刪除（通過 prune 參數），node12 已經是 “left" 狀態了，執行如下命令：

./consul force-leave -prune node12

再查看節點信息如下：

Node     Address             Status  Type    Build   Protocol  DC   Partition  Segment
node10   10.49.196.10:8301   alive   server  1.11.1  2         dc1  default    <all>
node11   10.49.196.11:8301   alive   server  1.11.1  2         dc1  default    <all>

3、多數據中心

3.1、規划

在上一步搭建的集群上，我們再搭建一個不通數據中心的集群，組成跨數據中心集群。

機器	agent 類型	數據中心名稱
10.49.196.10	server	dc1
10.49.196.11	server	dc1
10.49.196.12	server	dc1
10.49.196.20	server	dc2
10.49.196.21	client	dc2

3.2、啟動 dc2 的節點

nohup ./consul agent -config-file=./agent.hcl &

10.49.196.20 上 agent.hcl:

server = true,
ui_config = {
  enabled = true
},
bootstrap_expect = 1,
data_dir = "./data",
datacenter = "dc2",
node_name = "node20",
client_addr = "0.0.0.0",
bind_addr = "10.49.196.20"

10.49.196.21 上 agent.hcl:

server = false,
ui_config = {
  enabled = true
},
data_dir = "./data",
datacenter = "dc2",
node_name = "node21",
client_addr = "0.0.0.0",
bind_addr = "10.49.196.21",
start_join = ["10.49.196.20"],
retry_join = ["10.49.196.20"],

3.3、加入 dc1

在 10.49.196.20（需為 server 節點）上執行：

./consul join -wan 10.49.196.10

3.4、管理

3.4.1、查看所有 server 節點

./consul members -wan

該命令可以查看所以數據中心的 server 類型的節點：

Node        Address              Status  Type    Build   Protocol  DC   Partition  Segment
node10.dc1  10.49.196.10:8302    alive   server  1.11.1  2         dc1  default    <all>
node11.dc1  10.49.196.11:8302    alive   server  1.11.1  2         dc1  default    <all>
node12.dc1  10.49.196.12:8302    alive   server  1.11.1  2         dc1  default    <all>
node20.dc2  10.49.196.20:8302    alive   server  1.11.1  2         dc2  default    <all>

查看某個數據中心的所有節點信息可用：

./consul members [-http-addr=<address>]

3.4.2、斷開數據中心的關聯

1、在 10.49.196.20 上執行：

./consul leave

2、在 10.49.196.10、10.49.196.11、10.49.196.12 人一台集群上執行：

./consul force-leave -prune -wan node20.dc2

3、在 10.49.196.20 再啟動 consul：

nohup ./consul agent -config-file=./agent.hcl &

4、命令行使用

可以通過執行 consul 命令后的提示來學習如何使用命令行，如執行：

./consul

提示如下：

Usage: consul [--version] [--help] <command> [<args>]

Available commands are:
    acl            Interact with Consul's ACLs
    agent          Runs a Consul agent
    catalog        Interact with the catalog
    config         Interact with Consul's Centralized Configurations
    connect        Interact with Consul Connect
    debug          Records a debugging archive for operators
    event          Fire a new event
    exec           Executes a command on Consul nodes
    force-leave    Forces a member of the cluster to enter the "left" state
    info           Provides debugging information for operators.
    intention      Interact with Connect service intentions
    join           Tell Consul agent to join cluster
    keygen         Generates a new encryption key
    keyring        Manages gossip layer encryption keys
    kv             Interact with the key-value store
    leave          Gracefully leaves the Consul cluster and shuts down
    lock           Execute a command holding a lock
    login          Login to Consul using an auth method
    logout         Destroy a Consul token created with login
    maint          Controls node or service maintenance mode
    members        Lists the members of a Consul cluster
    monitor        Stream logs from a Consul agent
    operator       Provides cluster-level tools for Consul operators
    reload         Triggers the agent to reload configuration files
    rtt            Estimates network round trip time between nodes
    services       Interact with services
    snapshot       Saves, restores and inspects snapshots of Consul server state
    tls            Builtin helpers for creating CAs and certificates
    validate       Validate config files/directories
    version        Prints the Consul version
    watch          Watch for changes in Consul

如需查看 members 指令的用法，再執行：

./consul members -h

就會顯示用法及各種參數，參數是可選的：

Usage: consul members [options]

  Outputs the members of a running Consul agent.

HTTP API Options

  -ca-file=<value>
     Path to a CA file to use for TLS when communicating with Consul.
     This can also be specified via the CONSUL_CACERT environment
     variable.

  -ca-path=<value>
     Path to a directory of CA certificates to use for TLS when
     communicating with Consul. This can also be specified via the
     CONSUL_CAPATH environment variable.

  -client-cert=<value>
     Path to a client cert file to use for TLS when 'verify_incoming'
     is enabled. This can also be specified via the CONSUL_CLIENT_CERT
     environment variable.

  -client-key=<value>
     Path to a client key file to use for TLS when 'verify_incoming'
     is enabled. This can also be specified via the CONSUL_CLIENT_KEY
     environment variable.

  -http-addr=<address>
     The `address` and port of the Consul HTTP agent. The value can be
     an IP address or DNS address, but it must also include the port.
     This can also be specified via the CONSUL_HTTP_ADDR environment
     variable. The default value is http://127.0.0.1:8500. The scheme
     can also be set to HTTPS by setting the environment variable
     CONSUL_HTTP_SSL=true.

  -tls-server-name=<value>
     The server name to use as the SNI host when connecting via
     TLS. This can also be specified via the CONSUL_TLS_SERVER_NAME
     environment variable.

  -token=<value>
     ACL token to use in the request. This can also be specified via the
     CONSUL_HTTP_TOKEN environment variable. If unspecified, the query
     will default to the token of the Consul agent at the HTTP address.

  -token-file=<value>
     File containing the ACL token to use in the request instead of one
     specified via the -token argument or CONSUL_HTTP_TOKEN environment
     variable. This can also be specified via the CONSUL_HTTP_TOKEN_FILE
     environment variable.

Command Options

  -detailed
     Provides detailed information about nodes.

  -partition=<default>
     Specifies the admin partition to query. If not provided, the admin
     partition will be inferred from the request's ACL token, or will
     default to the `default` admin partition. Admin Partitions are a
     Consul Enterprise feature.

  -segment=<string>
     (Enterprise-only) If provided, output is filtered to only nodes
     inthe given segment.

  -status=<string>
     If provided, output is filtered to only nodes matching the regular
     expression for status.

  -wan
     If the agent is in server mode, this can be used to return the
     other peers in the WAN pool.

最后知道執行如下命令就可以查看節點信息：

./consul members