15-底层原理

Mon, 06 Apr 2026 17:55:53 +0800

控制面组件工作原理

Etcd

安装

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ETCD_VER=v3.5.21

# choose either URL
GITHUB_URL=https://github.com/etcd-io/etcd/releases/download
DOWNLOAD_URL=${GOOGLE_URL}

rm -f /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz
rm -rf /tmp/etcd-download-test && mkdir -p /tmp/etcd-download-test

curl -L ${DOWNLOAD_URL}/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz -o /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz
tar xzvf /tmp/etcd-${ETCD_VER}-linux-amd64.tar.gz -C /tmp/etcd-download-test --strip-components=1

/tmp/etcd-download-test/etcd --version
/tmp/etcd-download-test/etcdctl version

启动服务

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# ./etcd
WARNING: Package "github.com/golang/protobuf/protoc-gen-go/generator" is deprecated.
 A future release of golang/protobuf will delete this package,
 which has long been excluded from the compatibility promise.

列出集群成员

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# ./etcdctl --endpoints=localhost:2379 member list --write-out=table 
+------------------+---------+---------+-----------------------+-----------------------+------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS | IS LEARNER |
+------------------+---------+---------+-----------------------+-----------------------+------------+
| 8e9e05c52164694d | started | default | http://localhost:2380 | http://localhost:2379 | false |
+------------------+---------+---------+-----------------------+-----------------------+------------+

写入操作

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# 写入数据
./etcdctl --endpoints=localhost:2379 put /key1 val1
OK

# 读取数据
./etcdctl --endpoints=localhost:2379 get /key1
/key1
val1

# 按 Key 的前缀查询数据
./etcdctl --endpoints=localhost:2379 get --prefix /
/key1
val1

# 只显示键值
./etcdctl --endpoints=localhost:2379 get --prefix / --keys-only
/key1

# watch key 变化 
./etcdctl --endpoints=localhost:2379 watch --prefix /
./etcdctl --endpoints=localhost:2379 put /name k1s
./etcdctl --endpoints=localhost:2379 put /name k2s
./etcdctl --endpoints=localhost:2379 put /name k3s
./etcdctl --endpoints=localhost:2379 put /name k4s
./etcdctl --endpoints=localhost:2379 get /name -wjson

./etcdctl --endpoints=localhost:2379 watch --prefix /name --rev 1
PUT
/name
k1s
PUT
/name
k2s
PUT
/name
k3s
PUT
/name
k4s

灾备

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# 声明 环境变量
export ETCDCTL_API=3
export ENDPOINTS=localhost:2379

# 备份 
$ etcdctl --endpoints=${ENDPOINTS} snapshot save /data/etcd_backup_dir/etcd-snapshot.db

# 还原
$ etcdutl --data-dir=/data/etcd/etcd-restore snapshot restore /data/etcd_backup_dir/etcd-snapshot.db

Kubernetes 数据如何保存在 etcd 中

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export ETCDCTL_API=3



在pod里面访问

kubectl exec -it etcd-master-01 -n kube-system -- sh



etcdctl --endpoints https://localhost:2379 --cert /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key --cacert /etc/kubernetes/pki/etcd/ca.crt get --keys-only --prefix /

etcdctl --endpoints https://localhost:2379 --cert /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key --cacert /etc/kubernetes/pki/etcd/ca.crt get --keys-only --prefix /registry/pods/default/redis-pv-sts-0

etcdctl --endpoints https://localhost:2379 --cert /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key --cacert /etc/kubernetes/pki/etcd/ca.crt get /registry/pods/default/redis-pv-sts-0

etcdctl --endpoints https://localhost:2379 --cert /etc/kubernetes/pki/etcd/server.crt --key /etc/kubernetes/pki/etcd/server.key --cacert /etc/kubernetes/pki/etcd/ca.crt get /registry/configmaps/default/info

Etcd 备份脚本

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#!/bin/bash

ETCDCTL_PATH='/usr/local/bin/etcdctl'
ENDPOINTS='https://192.168.200.153:2379'
ETCD_DATA_DIR="/var/lib/etcd"
BACKUP_DIR="/var/backups/kube_etcd/etcd-$(date +%Y-%m-%d-%H-%M-%S)"
KEEPBACKUPNUMBER='5'
ETCDBACKUPPERIOD='30'
ETCDBACKUPSCIPT='/usr/local/bin/kube-scripts'
ETCDBACKUPHOUR=''

ETCDCTL_CERT="/etc/ssl/etcd/ssl/admin-master1.pem"
ETCDCTL_KEY="/etc/ssl/etcd/ssl/admin-master1-key.pem"
ETCDCTL_CA_FILE="/etc/ssl/etcd/ssl/ca.pem"

[ ! -d $BACKUP_DIR ] && mkdir -p $BACKUP_DIR

export ETCDCTL_API=2;$ETCDCTL_PATH backup --data-dir $ETCD_DATA_DIR --backup-dir $BACKUP_DIR

sleep 3

{
export ETCDCTL_API=3;$ETCDCTL_PATH --endpoints="$ENDPOINTS" snapshot save $BACKUP_DIR/snapshot.db \
 --cacert="$ETCDCTL_CA_FILE" \
 --cert="$ETCDCTL_CERT" \
 --key="$ETCDCTL_KEY"
} > /dev/null

sleep 3

cd $BACKUP_DIR/../;ls -lt |awk '{if(NR > '$KEEPBACKUPNUMBER'){print "rm -rf "$9}}'|sh

if [[ ! $ETCDBACKUPHOUR ]]; then
 time="*/$ETCDBACKUPPERIOD * * * *"
else
 if [[ 0 == $ETCDBACKUPPERIOD ]];then
 time="* */$ETCDBACKUPHOUR * * *"
 else
 time="*/$ETCDBACKUPPERIOD */$ETCDBACKUPHOUR * * *"
 fi
fi

crontab -l | grep -v '#' > /tmp/file
echo "$time sh $ETCDBACKUPSCIPT/etcd-backup.sh" >> /tmp/file && awk ' !x[$0]++{print > "/tmp/file"}' /tmp/file
crontab /tmp/file
rm -rf /tmp/file