浅谈云原生技术组件—etcd

root@ymx-ubuntu:/usr/local# wget https://github.com/etcd-io/etcd/releases/download/v3.5.4/etcd-v3.5.4-linux-amd64.tar.gz
......
2022-05-15 14:20:34 (1.45 MB/s) - 已保存 “etcd-v3.5.4-linux-amd64.tar.gz” [19432359/19432359])
root@ymx-ubuntu:/usr/local# ls
etcd-v3.5.4-linux-amd64.tar.gz ......
root@ymx-ubuntu:/usr/local# tar -zxvf etcd-v3.5.4-linux-amd64.tar.gz 
......
root@ymx-ubuntu:/usr/local# cd etcd-v3.5.4-linux-amd64/
root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ls -al
总用量 56300
drwxr-xr-x  3 528287 89939     4096 4月  24 18:45 .
drwxr-xr-x 14 root   root      4096 5月  15 14:20 ..
drwxr-xr-x  3 528287 89939     4096 4月  24 18:45 Documentation
-rwxr-xr-x  1 528287 89939 23564288 4月  24 18:45 etcd
-rwxr-xr-x  1 528287 89939 17960960 4月  24 18:45 etcdctl
-rwxr-xr-x  1 528287 89939 16039936 4月  24 18:45 etcdutl
-rw-r--r--  1 528287 89939    42066 4月  24 18:45 README-etcdctl.md
-rw-r--r--  1 528287 89939     7359 4月  24 18:45 README-etcdutl.md
-rw-r--r--  1 528287 89939     9394 4月  24 18:45 README.md
-rw-r--r--  1 528287 89939     7896 4月  24 18:45 READMEv2-etcdctl.md
root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcd -version
etcd Version: 3.5.4
Git SHA: 0xxxxxx
Go Version: go1.16.15
Go OS/Arch: linux/amd64
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root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# vim /etc/profile
#### 在文件末尾加入以下内容
export ETCD_HOME=/usr/local/etcd-v3.5.4-linux-amd64
export PATH=$PATH:$ETCD_HOME
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TOKEN=my_etcd
CLUSTER_STATE=new
NAME_1=my_etcd_name
HOST_1=127.0.0.1
CLUSTER=${NAME_1}=http://${HOST_1}:2380
THIS_NAME=${NAME_1}
THIS_IP=${HOST_1}
etcd --data-dir=data.etcd --name ${THIS_NAME} \
  --initial-advertise-peer-urls http://${THIS_IP}:2380 --listen-peer-urls http://${THIS_IP}:2380 \
  --advertise-client-urls http://${THIS_IP}:2379 --listen-client-urls http://${THIS_IP}:2379 \
  --initial-cluster ${CLUSTER} \
  --initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}
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etcdctl --endpoints=127.0.0.1:2379 member list
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root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --endpoints=127.0.0.1:2379 member list
xxxxxxxx, started, my_etcd_name, http://127.0.0.1:2380, http://127.0.0.1:2379, false
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ENDPOINTS=127.0.0.1:2379
etcdctl --endpoints=$ENDPOINTS put foo "Hello World!"
etcdctl --endpoints=$ENDPOINTS get foo
etcdctl --endpoints=$ENDPOINTS --write-out="json" get foo
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root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --endpoints=$ENDPOINTS put foo "Hello World!"
OK
root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --endpoints=$ENDPOINTS get foo
foo
Hello World!
root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --endpoints=$ENDPOINTS --write-out="json" get foo
{"header":{"cluster_id":87772999870000089,"member_id":10756500090258089453,"revision":3,"raft_term":2},"kvs":[{"key":"Zm9v","create_revision":2,"mod_revision":3,"version":2,"value":"SGV00000ybGQh"}],"count":1}
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ENDPOINTS=127.0.0.1:2379
etcdctl --endpoints=$ENDPOINTS snapshot save my.db
etcdctl --write-out=table --endpoints=$ENDPOINTS snapshot status my.db
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root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --endpoints=$ENDPOINTS snapshot save my.db
......
Snapshot saved at my.db
root@ymx-ubuntu:/usr/local/etcd-v3.5.4-linux-amd64# ./etcdctl --write-out=table --endpoints=$ENDPOINTS snapshot status my.db
Deprecated: Use `etcdutl snapshot status` instead.
+----------+----------+------------+------------+
|   HASH   | REVISION | TOTAL KEYS | TOTAL SIZE |
+----------+----------+------------+------------+
| ebfb411d |        3 |          8 |      20 kB |
+----------+----------+------------+------------+
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func main() {
   cli, err := clientv3.New(clientv3.Config{
      Endpoints:   []string{"127.0.0.1:2379"},
      DialTimeout: 5 * time.Second,
   })
   if err != nil {
      panic(err)
   }
   resp, err := cli.Put(context.TODO(), "sample_key", "sample_value")
   fmt.Println(resp)
   response, err := cli.Get(context.TODO(), "sample_key")
   fmt.Println(response)
   defer cli.Close()
}
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<dependency>
  <groupId>io.etcd</groupId>
  <artifactId>jetcd-core</artifactId>
  <version>0.5.0</version>
</dependency>
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@Test
void TestEtcd() throws Exception {
    //集群模式下可以使用逗号分隔
    Client client = Client.builder().endpoints("http://127.0.0.1:2379").build();
    KV kvClient = client.getKVClient();
    ByteSequence key = ByteSequence.from("test_key".getBytes());
    ByteSequence value = ByteSequence.from("test_value".getBytes());
    // put值
    kvClient.put(key, value).get();
    // get值
    CompletableFuture<GetResponse> getFuture = kvClient.get(key);
    GetResponse response = getFuture.get();
    System.out.println(response);
    // 删除值
    kvClient.delete(key).get();
}
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