8.4 KiB
8.4 KiB
Demo
This series of examples shows the basic procedures for working with an etcd cluster.
Set up a cluster
![01_etcd_clustering_2016050601](https://storage.googleapis.com/etcd/demo/01_etcd_clustering_2016051001.gif)
On each etcd node, specify the cluster members:
TOKEN=token-01
CLUSTER_STATE=new
NAME_1=machine-1
NAME_2=machine-2
NAME_3=machine-3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
CLUSTER=${NAME_1}=http://${HOST_1}:2380,${NAME_2}=http://${HOST_2}:2380,${NAME_3}=http://${HOST_3}:2380
Run this on each machine:
# For machine 1
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 ${TOKEN}
# For machine 2
THIS_NAME=${NAME_2}
THIS_IP=${HOST_2}
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 ${TOKEN}
# For machine 3
THIS_NAME=${NAME_3}
THIS_IP=${HOST_3}
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 ${TOKEN}
Or use our public discovery service:
curl https://discovery.etcd.io/new?size=3
https://discovery.etcd.io/a81b5818e67a6ea83e9d4daea5ecbc92
# grab this token
TOKEN=token-01
CLUSTER_STATE=new
NAME_1=machine-1
NAME_2=machine-2
NAME_3=machine-3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
DISCOVERY=https://discovery.etcd.io/a81b5818e67a6ea83e9d4daea5ecbc92
THIS_NAME=${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 \
--discovery ${DISCOVERY} \
--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}
THIS_NAME=${NAME_2}
THIS_IP=${HOST_2}
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 \
--discovery ${DISCOVERY} \
--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}
THIS_NAME=${NAME_3}
THIS_IP=${HOST_3}
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 \
--discovery ${DISCOVERY} \
--initial-cluster-state ${CLUSTER_STATE} --initial-cluster-token ${TOKEN}
Now etcd is ready! To connect to etcd with etcdctl:
export ETCDCTL_API=3
HOST_1=10.240.0.17
HOST_2=10.240.0.18
HOST_3=10.240.0.19
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
etcdctl --endpoints=$ENDPOINTS member list
Access etcd
![02_etcdctl_access_etcd_2016051001](https://storage.googleapis.com/etcd/demo/02_etcdctl_access_etcd_2016051001.gif)
put
command to write:
etcdctl --endpoints=$ENDPOINTS put foo "Hello World!"
get
to read from etcd:
etcdctl --endpoints=$ENDPOINTS get foo
etcdctl --endpoints=$ENDPOINTS --write-out="json" get foo
Get by prefix
![03_etcdctl_get_by_prefix_2016050501](https://storage.googleapis.com/etcd/demo/03_etcdctl_get_by_prefix_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS put web1 value1
etcdctl --endpoints=$ENDPOINTS put web2 value2
etcdctl --endpoints=$ENDPOINTS put web3 value3
etcdctl --endpoints=$ENDPOINTS get web --prefix
Delete
![04_etcdctl_delete_2016050601](https://storage.googleapis.com/etcd/demo/04_etcdctl_delete_2016050601.gif)
etcdctl --endpoints=$ENDPOINTS put key myvalue
etcdctl --endpoints=$ENDPOINTS del key
etcdctl --endpoints=$ENDPOINTS put k1 value1
etcdctl --endpoints=$ENDPOINTS put k2 value2
etcdctl --endpoints=$ENDPOINTS del k --prefix
Transactional write
txn
to wrap multiple requests into one transaction:
![05_etcdctl_transaction_2016050501](https://storage.googleapis.com/etcd/demo/05_etcdctl_transaction_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS put user1 bad
etcdctl --endpoints=$ENDPOINTS txn --interactive
compares:
value("user1") = "bad"
success requests (get, put, delete):
del user1
failure requests (get, put, delete):
put user1 good
Watch
watch
to get notified of future changes:
![06_etcdctl_watch_2016050501](https://storage.googleapis.com/etcd/demo/06_etcdctl_watch_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS watch stock1
etcdctl --endpoints=$ENDPOINTS put stock1 1000
etcdctl --endpoints=$ENDPOINTS watch stock --prefix
etcdctl --endpoints=$ENDPOINTS put stock1 10
etcdctl --endpoints=$ENDPOINTS put stock2 20
Lease
lease
to write with TTL:
![07_etcdctl_lease_2016050501](https://storage.googleapis.com/etcd/demo/07_etcdctl_lease_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS lease grant 300
# lease 2be7547fbc6a5afa granted with TTL(300s)
etcdctl --endpoints=$ENDPOINTS put sample value --lease=2be7547fbc6a5afa
etcdctl --endpoints=$ENDPOINTS get sample
etcdctl --endpoints=$ENDPOINTS lease keep-alive 2be7547fbc6a5afa
etcdctl --endpoints=$ENDPOINTS lease revoke 2be7547fbc6a5afa
# or after 300 seconds
etcdctl --endpoints=$ENDPOINTS get sample
Distributed locks
lock
for distributed lock:
![08_etcdctl_lock_2016050501](https://storage.googleapis.com/etcd/demo/08_etcdctl_lock_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS lock mutex1
# another client with the same name blocks
etcdctl --endpoints=$ENDPOINTS lock mutex1
Elections
elect
for leader election:
![09_etcdctl_elect_2016050501](https://storage.googleapis.com/etcd/demo/09_etcdctl_elect_2016050501.gif)
etcdctl --endpoints=$ENDPOINTS elect one p1
# another client with the same name blocks
etcdctl --endpoints=$ENDPOINTS elect one p2
Cluster status
Specify the initial cluster configuration for each machine:
![10_etcdctl_endpoint_2016050501](https://storage.googleapis.com/etcd/demo/10_etcdctl_endpoint_2016050501.gif)
etcdctl --write-out=table --endpoints=$ENDPOINTS endpoint status
+------------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+------------------+------------------+---------+---------+-----------+-----------+------------+
| 10.240.0.17:2379 | 4917a7ab173fabe7 | 3.0.0 | 45 kB | true | 4 | 16726 |
| 10.240.0.18:2379 | 59796ba9cd1bcd72 | 3.0.0 | 45 kB | false | 4 | 16726 |
| 10.240.0.19:2379 | 94df724b66343e6c | 3.0.0 | 45 kB | false | 4 | 16726 |
+------------------+------------------+---------+---------+-----------+-----------+------------+
etcdctl --endpoints=$ENDPOINTS endpoint health
10.240.0.17:2379 is healthy: successfully committed proposal: took = 3.345431ms
10.240.0.19:2379 is healthy: successfully committed proposal: took = 3.767967ms
10.240.0.18:2379 is healthy: successfully committed proposal: took = 4.025451ms
Snapshot
snapshot
to save point-in-time snapshot of etcd database:
![11_etcdctl_snapshot_2016051001](https://storage.googleapis.com/etcd/demo/11_etcdctl_snapshot_2016051001.gif)
etcdctl --endpoints=$ENDPOINTS snapshot save my.db
Snapshot saved at my.db
etcdctl --write-out=table --endpoints=$ENDPOINTS snapshot status my.db
+---------+----------+------------+------------+
| HASH | REVISION | TOTAL KEYS | TOTAL SIZE |
+---------+----------+------------+------------+
| c55e8b8 | 9 | 13 | 25 kB |
+---------+----------+------------+------------+