部署前先考虑mysql在Kubernetes中需要的过程细节
维持集群状态需要知道各个节点ip,但是需要实时监控po ip很困难。可不可以利用动态dns那种ip与域名自动映射,到时候直接用域名访问是不是更简单。所以可以借助coredns的能力。
集群搭建,我需要对外提供四层服务那么就需要NodePort Service。而维持集群状态我需要集群发现功能作用把域名给我解析成地址那么要Headless Service
因为集群重启有序,并且涉及数据持久化挂掉恢复或者重启还能自动连接。那么满足这些需求的就只剩sts。因为deploy创建的pod名字与容器内名字不固定,而恰恰存储类会用到一些po名字的相关信息(命名规则:deploy.name+rs.name+hash)重启po ip会变,持久化也会因为重启名字变更而且不能自动恢复,最严重启动无序导致集群混乱异常。
组件缩写:
deploy: Deployment
sts: StatefulSet
po: Pod
cm: ConfigMap
sc: StorageClass
pv: PersistentVolumeClaim
pvc: PersistentVolume
1、部署需求
1). 是主从复制集群
2). 有1个或者多个节点(本例单主)
3). 从节点可以横向扩缩
4). 所有写操作只能在主节点,读在所有节点都可读取
5). 如果MySql容器进程挂掉或主从异常能重启自动恢复
6). 主节点挂掉能自动恢复
Master: write
Slave: read
Master index = 0
Slave index = 1 or 2
index根据hostname抓取后面的id取值即可,因为sts的pod内容器命名规则是sts name+id形成,id就可以作为索引。因为sts中pod启动顺序是有序的,所以不怕混乱,挂掉恢复也会保持。
Xtrabackup
注:都知道这个是mysql备份工具,有一点要注意,8.0版本能备份之前版本的mysql,而8.0之后只能备份8.0以上的mysql数据库
Xtrabackup备份后会生成一些文件
1)、 xtrabackup开头的都是
[root@master mysql-statefulset-pod]# kubectl exec -it pod/mysql-0 -n mysql -c mysql -- bash root@mysql-1:/var/lib/mysql# ls ‘#innodb_temp‘ ca-key.pem ib_logfile0 mysql-0-bin.index private_key.pem undo_002 xtrabackup_master_key_id auto.cnf ca.pem ib_logfile1 mysql-1-relay-bin.000001 public_key.pem xtrabackup_backupfiles xtrabackup_slave_info backup-my.cnf change_master_to.sql.orig ibdata1 mysql-1-relay-bin.000002 server-cert.pem xtrabackup_binlog_info xtrabackup_tablespaces binlog.000001 client-cert.pem ibtmp1 mysql-1-relay-bin.index server-key.pem xtrabackup_checkpoints binlog.000002 client-key.pem mysql mysql.ibd sys xtrabackup_info binlog.index ib_buffer_pool mysql-0-bin.000004 performance_schema undo_001 xtrabackup_logfile root@mysql-1:/var/lib/mysql#
2)、 备份的信息
root@mysql-1:/var/lib/mysql# cat xtrabackup_info uuid = 1668c169-a3d1-11eb-a3a8-72033cfab7a8 name = tool_name = xtrabackup tool_command = --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root tool_version = 8.0.9 ibbackup_version = 8.0.9 server_version = 8.0.19 start_time = 2021-04-23 01:13:12 end_time = 2021-04-23 01:13:18 lock_time = 0 binlog_pos = filename ‘mysql-0-bin.000004‘, position ‘155‘ innodb_from_lsn = 0 innodb_to_lsn = 31267893 partial = N incremental = N format = xbstream compressed = N encrypted = N
3)、 主从CHANGE MASTER TO中的MASTER_LOG_FILE与MASTER_LOG_POS的信息就在这取
root@mysql-1:/var/lib/mysql# cat xtrabackup_binlog_info mysql-0-bin.000004 155
4)、 这个文件在恢复数据时会先检查它如果没有就报错,同样这个在用xtrabackup增量备份的时候会检查其中的LAST_LSN如果大于这个值就开始增量备份
root@mysql-1:/var/lib/mysql# cat xtrabackup_checkpoints backup_type = full-prepared from_lsn = 0 to_lsn = 31267404 last_lsn = 31267414 flushed_lsn = 0
5)、 这个文件是空的可以在后面判断用这个判断主从复制的,是从主节点来的数据,还是从从节点来的数据。主节点过来的数据虽然有这个文件但是文件是空的,而从节点过来的是有数据的。
root@mysql-1:/var/lib/mysql# cat xtrabackup_slave_info root@mysql-1:/var/lib/mysql#
正文:
Kubernetes跑Mysql自动主从流程
1、 先从xtrabackup中截取MASTER_LOG_FILE and MASTER_LOG_POS
2、 判断机器索引是否为0,如果是那么为主节点跳过,否则就是从节点那么就需要执行CHANGE MASTER TO配置
3、启动从节点
4、加入其他从节点
目前涉及有三个点:
1、主节点与从节点my.cnf配置不同需要区分开
2、节点之间需要传输数据
3、从节点第一执行需要一些初始设定,而且重启需要防止第一个从节点二次初始化。(例如:CHANGE MASTER TO)
先解决第一个问题
1)、 配置文件不同,那就在一个cm下以不同的key,定义不同的配置。然后根据判断index后copy过去,可以用initcontainer搞这个事情
apiVersion: v1 kind: ConfigMap metadata: name: mysql namespace: mysql labels: app: mysql data: master.cnf: | [client] default-character-set=utf8mb4 [mysql] default-character-set=utf8mb4 [mysqld] log-bin binlog_expire_logs_seconds=2592000 max_connections=1000000 binlog_format=MIXED default-time-zone=‘+8:00‘ character-set-client-handshake=FALSE character-set-server=utf8mb4 collation-server=utf8mb4_unicode_ci init_connect=‘SET NAMES utf8mb4 COLLATE utf8mb4_unicode_ci‘ slave.cnf: | [client] default-character-set=utf8mb4 [mysql] default-character-set=utf8mb4 [mysqld] super-read-only max_connections=1000000 binlog_format=MIXED
# 下面三条结尾介绍配置原因 relay_log_info_repository=table master_info_repository=table relay_log_recovery = 1 default-time-zone=‘+8:00‘ character-set-client-handshake=FALSE character-set-server=utf8mb4 collation-server=utf8mb4_unicode_ci init_connect=‘SET NAMES utf8mb4 COLLATE utf8mb4_unicode_ci‘
判断索引
initContainers:
- name: init-mysql
image: mysql:8.0.19
imagePullPolicy: IfNotPresent
command:
- bash
- "-c"
- |
set -ex
# 从hostname中去index,例子:mysql-0去的就是后边的0。 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
# BASH_REMATCH[x]取组,配合shell中的( )使用,匹配的括号内正则匹配的值。
# 取值赋给myinde变量,如果严格来写,记得变量大写。我比较懒,都小写了。 myindex=${BASH_REMATCH[1]}
echo [mysqld] > /mnt/conf.d/server-id.cnf
echo server-id=$((100 + ${myindex})) >> /mnt/conf.d/server-id.cnf
if [[ ${myindex} -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
2)、 传输文件可以用ncat来进行
只接受文件,但是这个实际还有一层意思。是向mysql-[id] 3307发送请求。initcontainer下的clone-mysql
ncat --recv-only mysql-$((${myindex}-1)).mysql 3307
只3307端口,收到请求,发送数据。container下的xtrabackup
exec ncat --listen --keep-open --send-only --max-conns=1 3307
3)、 从节点第一执行需要一些初始设定,并防止重启或恢复后二次初始化主从配置。(例如:CHANGE MASTER TO)
containers: - name: xtrabackup image: mzmuer/xtrabackup:1.0 imagePullPolicy: IfNotPresent ports: - name: xtrabackup containerPort: 3307 command: - bash - "-c" - | set -ex
# 进入数据目录(或者说要备份或恢复的目录) cd /var/lib/mysql
# 如果这个文件有数据,证明,这是从从节点传输过来的。(-s)如果有数据就成立
# 如果没有数据有xtrabackup_binlog_info,就会认为是从主节点过来的,但是若不是,会因为判断错误导致change_master_to.sql.in再次被重写,影响后续第一个从节点之后所有以后节点的主从配置(因为第二次copy的binlog中是slave的binlog信息与偏移量)
# 所以xtrabackup_binlog_info这个存在会影响判断变更结果,所以需要删除。 if [[ -s xtrabackup_slave_info ]]; then
# 直接改名 mv xtrabackup_slave_info change_master_to.sql.in
# 如果不删除会继续下面elif的判断,不删除的条件成立会继续执行导致文件变更。 rm -f xtrabackup_binlog_info
# 如果这个文件存在,证明数据是从主节点传输过来的。 elif [[ -f xtrabackup_binlog_info ]]; then
# 那么,取其中值因为中间是空格分割所以用了[[:space:]]配合两端()用BASH_REMATCH取值。 [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
# 取到的值以换行回车方式存储到change_master_to.sql.in echo -e "CHANGE MASTER TO\nMASTER_LOG_FILE=‘${BASH_REMATCH[1]}‘,\nMASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
# 删除为了如果容器重启第一个从节点二次初始化。 rm -f xtrabackup_binlog_info fi if [[ -f change_master_to.sql.in ]]; then echo "Waiting for mysqld to be ready (accepting connections)" until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done echo "Initializing replication from clone position" mv change_master_to.sql.in change_master_to.sql.orig mysql -h 127.0.0.1 <<EOF $(<change_master_to.sql.orig), MASTER_HOST=‘mysql-0.mysql‘, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘repl123.‘, MASTER_CONNECT_RETRY=10; START SLAVE; EOF echo "master slave config ok" fi
配置对外提供四层服务与维持集群状态的Service(两个)
apiVersion: v1
kind: Service
metadata:
name: mysql
namespace: mysql
labels:
app: mysql
spec:
selector:
app: mysql
ports:
- name: mysql
port: 3306
clusterIP: None --- apiVersion: v1
kind: Service
metadata:
name: mysql-read
namespace: mysql
labels:
app: mysql
spec:
selector:
app: mysql
ports:
- name: mysql
port: 3306
先写主题框架:
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: mysql
namespace: mysql
spec:
replicas: 3
selector:
matchLabels:
app: mysql
serviceName: mysql
template:
metadata:
labels:
app: mysql
spec:
# 初始化容器 initContainers:
# 初始化master或slave配置文件用 - name: init-mysql
image: mysql:8.0.19
# 本地有镜像就直接用没有才下载 imagePullPolicy: IfNotPresent
# 从节点复制备份文件用 - name: clone-mysql
image: mzmuer/xtrabackup:1.0
imagePullPolicy: IfNotPresent
containers:
# 主要服务容器 - name: mysql
image: mysql:8.0.19
imagePullPolicy: IfNotPresent
ports:
# 容器接口 - name: mysql
containerPort: 3306
# master or slave初始化主从配置 - name: xtrabackup
image: mzmuer/xtrabackup:1.0
imagePullPolicy: IfNotPresent
ports:
- name: xtrabackup
containerPort: 3307
# 初始化配置文件所有的共享存储 volumes:
- name: conf
emptyDir: {}
# 数据文件存储 - name: config-map
configMap:
# cm的名字 name: mysql
# 创建pvc使用这个模板 volumeClaimTemplates:
- metadata:
name: data
spec:
# 存储类名字sc名 storageClassName: "managed-nfs-storage"
# 匹配pv的一个参数,读写权限 accessModes: ["ReadWriteMany"]
resources:
requests:
# 匹配pv的指标容量 storage: 10Gi
填写初始化配置文件容器:
initContainers:
- name: init-mysql
image: mysql:8.0.19
imagePullPolicy: IfNotPresent
command:
- bash
- "-c"
- |
set -ex
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
myindex=${BASH_REMATCH[1]}
# 两个细节两个配置文件,第一个server-id.cnf里面记录的是集群内的成员id用来区分实例。 echo [mysqld] > /mnt/conf.d/server-id.cnf
# 向刚刚的server-id.cnf中写入server-id=100+id。 echo server-id=$((100 + ${myindex})) >> /mnt/conf.d/server-id.cnf
# 如果index为0,那么就拷贝cm中的master配置过去,其他就拷贝slave配置过去 if [[ ${myindex} -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
注:所有MySQL实例都要配置一个独一无二的server-id。默认值为0,当server-id=0时,虽然会记录二进制日志,如果在主节点,会拒绝所有的从节点连接。如果是从节点,会拒绝链接其他实例
server_id不能相同,因为用来决定是否执行event,相同就不执行
填写初始化复制文件容器:
initContainers: - name: clone-mysql image: mzmuer/xtrabackup:1.0 imagePullPolicy: IfNotPresent command: - bash - "-c" - | set -ex # 如果目录存在证明已经有数据了,退出。否则执行下一个判断。 [[ -d /var/lib/mysql/mysql ]] && exit 0 # 右侧正则表达式如果不成立退出 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
# 取上面正则表达式匹配的值 myindex=${BASH_REMATCH[1]} # 如果索引等于0是是主节点,退出 [[ ${myindex} -eq 0 ]] && exit 0 # 向mysql-[id] 3307 发起请求并只接受数据,并解压数据到/var/lib/mysql中(x解压C指定目录) ncat --recv-only mysql-$((${myindex}-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
# 恢复数据 xtrabackup --prepare --target-dir=/var/lib/mysql # --redo-only 加了会导致为提交的事务不回滚 volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d
填写主服务容器:
containers: - name: mysql image: mysql:8.0.19 imagePullPolicy: IfNotPresent args: ["--default-authentication-plugin=mysql_native_password"] env: - name: MYSQL_ALLOW_EMPTY_PASSWORD value: "1" ports: - name: mysql containerPort: 3306 volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: requests: cpu: 250m memory: 256Mi limits: cpu: 500m memory: 512Mi livenessProbe: exec: command: ["mysqladmin", "ping"] initialDelaySeconds: 30 periodSeconds: 10 timeoutSeconds: 5 readinessProbe: exec: command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"] initialDelaySeconds: 5 periodSeconds: 2 timeoutSeconds: 1
填写初始化配置容器:
containers: - name: xtrabackup image: mzmuer/xtrabackup:1.0 imagePullPolicy: IfNotPresent ports: - name: xtrabackup containerPort: 3307 command: - bash - "-c" - | set -ex # 进入数据目录(或者说要备份或恢复的目录) cd /var/lib/mysql
# 如果这个文件有数据,证明,这是从从节点传输过来的。(-s)如果有数据就成立
# 如果没有数据有xtrabackup_binlog_info,就会认为是从主节点过来的,但是若不是,会因为判断错误导致change_master_to.sql.in再次被重写,影响后续第一个从节点之后所有以后节点的主从配置(因为第二次copy的binlog中是slave的binlog信息与偏移量)
# 所以xtrabackup_binlog_info这个存在会影响判断变更结果,所以需要删除。
if [[ -s xtrabackup_slave_info ]]; then
# 直接改名 mv xtrabackup_slave_info change_master_to.sql.in
# 如果不删除会继续下面elif的判断,不删除的条件成立会继续执行导致文件变更。 rm -f xtrabackup_binlog_info
# 如果这个文件存在,证明数据是从主节点传输过来的。 elif [[ -f xtrabackup_binlog_info ]]; then
# 那么,取其中值因为中间是空格分割所以用了[[:space:]]配合两端()用BASH_REMATCH取值。 [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
# 取到的值以换行回车方式存储到change_master_to.sql.in echo -e "CHANGE MASTER TO\nMASTER_LOG_FILE=‘${BASH_REMATCH[1]}‘,\nMASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
# 删除为了如果容器重启第一个从节点二次重写change_master_to.sql.in执行后续初始化 rm -f xtrabackup_binlog_info fi if [[ -f change_master_to.sql.in ]]; then echo "Waiting for mysqld to be ready (accepting connections)"
# 检测服务是否启动 until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done echo "Initializing replication from clone position"
# 重命名防止重启在此检测初始化 mv change_master_to.sql.in change_master_to.sql.orig
# 初始化主从配置 mysql -h 127.0.0.1 <<EOF $(<change_master_to.sql.orig), MASTER_HOST=‘mysql-0.mysql‘, MASTER_USER=‘repl‘, MASTER_PASSWORD=‘repl123.‘, MASTER_CONNECT_RETRY=10; START SLAVE; EOF echo "master slave config ok" fi [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 myindex=${BASH_REMATCH[1]}
# 如果是主节点配置主从同步账户 if [[ ${myindex} -eq 0 ]]; then mysql -h 127.0.0.1 <<EOF use mysql; delete from user where user=‘repl‘ and host=‘%‘;flush privileges; CREATE USER ‘repl‘@‘%‘ IDENTIFIED WITH mysql_native_password BY ‘repl123.‘; GRANT REPLICATION SLAVE ON *.* TO ‘repl‘@‘%‘;flush privileges; SELECT Host, User, plugin from mysql.user; EOF else
# 获取主从健康状态 Slave_healthy=`mysql -h 127.0.0.1 -e ‘show slave status\G‘ 2> /dev/null |grep -E "Slave_IO_Running|Slave_SQL_Running"|awk ‘{print $2}‘|grep -c Yes` if [[ ${Slave_healthy} -eq 2 ]]; then echo "master slave healthy ok"
# 主从运行中需要停止刷新reloy_log然后开启从节点 elif [[ ${Slave_healthy} -eq 1 ]]; then echo "master slave healthy no" mysql -h 127.0.0.1 <<EOF stop slave; reset slave; start slave; EOF echo "master slave healthy revert"
# 主从为启动可能是reloy_log还是上一个节点信息导致,直接刷新开启从节点 elif [[ ${Slave_healthy} -eq 0 ]]; then echo "master slave healthy no" mysql -h 127.0.0.1 <<EOF reset slave; start slave; EOF echo "master slave healthy revert" fi fi
# 监听 3307 端口,如果收到请求。发送备份数据。 exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root" volumeMounts: - name: data mountPath: /var/lib/mysql subPath: mysql - name: conf mountPath: /etc/mysql/conf.d resources: requests: cpu: 100m memory: 100Mi limits: cpu: 200m memory: 200Mi
存储用的nfs,但是安装了插件使用了储存类,如果出异常,拍错方法如下:
1、现在nfs服务端查看/etc/exports配置文件,没有配置加配置
2、查看nfs服务状态,如果正常。使用exportfs -v查看信息
3、如果nfs服务状态异常,重启服务记得先启动rpcbind后启动nfs
4、上述正常在其他设备上showmount -e [nfs ip]查看挂在信息
都正常后,安装rbac deployment 与 class待sc出现即可使用nfs存储类
到此整体部署结束。
注:每次尾从节点有一个大坑。
如果CM配置文件slave.cnf部分没有relay_log_info_repository=table、master_info_repository=table和relay_log_recovery=1那么最后一个从节点,始终不会正常,原因我说在下面。
1 [root@master ~]# kubectl logs pod/mysql-2 -n mysql -c mysql 2 2021-04-23 08:53:50+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.19-1debian10 started. 3 2021-04-23 08:53:50+00:00 [Note] [Entrypoint]: Switching to dedicated user ‘mysql‘ 4 2021-04-23 08:53:50+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.19-1debian10 started. 5 2021-04-23T08:53:50.504572Z 0 [Warning] [MY-000081] [Server] option ‘max_connections‘: unsigned value 1000000 adjusted to 100000. 6 2021-04-23T08:53:50.969604Z 0 [Warning] [MY-011070] [Server] ‘Disabling symbolic links using --skip-symbolic-links (or equivalent) is the default. Consider not using this option as it‘ is deprecated and will be removed in a future release. 7 2021-04-23T08:53:50.969742Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.19) starting as process 1 8 2021-04-23T08:53:52.853035Z 0 [System] [MY-010229] [Server] Starting XA crash recovery... 9 2021-04-23T08:53:52.867197Z 0 [System] [MY-010232] [Server] XA crash recovery finished. 10 2021-04-23T08:53:52.937037Z 0 [Warning] [MY-010075] [Server] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 6dda8985-a411-11eb-9ed4-f223f4afe76a. 11 2021-04-23T08:53:53.754834Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed. 12 2021-04-23T08:53:53.964524Z 0 [Warning] [MY-011810] [Server] Insecure configuration for --pid-file: Location ‘/var/run/mysqld‘ in the path is accessible to all OS users. Consider choosing a different directory. 13 2021-04-23T08:53:54.042613Z 0 [Warning] [MY-010604] [Repl] Neither --relay-log nor --relay-log-index were used; so replication may break when this MySQL server acts as a slave and has his hostname changed!! Please use ‘--relay-log=mysql-2-relay-bin‘ to avoid this problem. 14 2021-04-23T08:53:54.106498Z 0 [ERROR] [MY-010544] [Repl] Failed to open the relay log ‘./mysql-1-relay-bin.000002‘ (relay_log_pos 204). 15 2021-04-23T08:53:54.106684Z 0 [ERROR] [MY-011059] [Repl] Could not find target log file mentioned in relay log info in the index file ‘./mysql-2-relay-bin.index‘ during relay log initialization. 16 2021-04-23T08:53:54.111596Z 0 [ERROR] [MY-010426] [Repl] Slave: Failed to initialize the master info structure for channel ‘‘; its record may still be present in ‘mysql.slave_master_info‘ table, consider deleting it. 17 2021-04-23T08:53:54.111764Z 0 [ERROR] [MY-010529] [Repl] Failed to create or recover replication info repositories. 18 2021-04-23T08:53:54.114091Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: ‘8.0.19‘ socket: ‘/var/run/mysqld/mysqld.sock‘ port: 3306 MySQL Community Server - GPL. 19 2021-04-23T08:53:54.177303Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Socket: ‘/var/run/mysqld/mysqlx.sock‘ bind-address: ‘::‘ port: 33060 20 2021-04-23T08:53:54.449627Z 9 [System] [MY-010597] [Repl] ‘CHANGE MASTER TO FOR CHANNEL ‘‘ executed‘. Previous state master_host=‘mysql-0.mysql‘, master_port= 3306, master_log_file=‘mysql-0-bin.000004‘, master_log_pos= 155, master_bind=‘‘. New state master_host=‘mysql-0.mysql‘, master_port= 3306, master_log_file=‘mysql-0-bin.000004‘, master_log_pos= 155, master_bind=‘‘.
标注部分提示找不到mysql-2-relay-bin.index文件。不是没有,但是不是在这个节点,是在上一个节点。因为是冷备文件恢复,所以导致Relay_log内容还是上一个节点的Relay_log,所以启动必报错。
而mysql-1-relay-bin.000002就是第一个从节点的Relay_log_name
1、relay log 文件:由IO thread线程从主库读取的二进制日志事件组成,该日志被Slave上的SQL thread线程执行,从而实现数据的复制。
2、master info log:该文件保存slave连接master的状态以及配置信息。在my.cnf 配置master-info-repository=table使用。这些信息会被写入slave_master_info 表中。替换早期版本的相关文件。
3、relay log info log:该文件保存slave上relay log的执行位置。在my.cnf中配置 relay-log-info-repository=table使用。用slave_relay_log_info表替换早期版本的相关文件。当slave上执行start slave时,就会读取表中的位置信息。
使用表替换原来的文件,是为了崩溃后的安全复制。大大提高从库的可靠性。为了保证意外情况下从库的可靠性。
reset slave作用:
1、删除slave_master_info ,slave_relay_log_info两个表中数据。
2、删除所有relay log文件,并重新创建新的relay log文件。
3、不会改变gtid_executed 或者 gtid_purged的值。
relay_log_recovery
打开该参数,在数据库启动后立即启动自动relay log恢复。在恢复过程中,创建一个新的relay log文件。将sql线程的位置初始化到新的relay log,并将i/o县城初始化到sql线程位置。
mysql在运行过程中,从库上可能会出现以外宕机的情况,那么在从库启动后,必须能够恢复到停止之前的状态。i/o县城必须恢复到接受事务的位置,sql县城必须恢复到一直执行事务的位置。用表来存储这些信息,并且把这些表设置为innodb引擎,通过使用事务性存储引擎,总能够恢复这个信息。可以配置参数master-info_repository=table和relay_log_info_repository=table使从库信息存储到表中。从库如何从宕机状态恢复到正确状态,取决与从库是单线程还是多线程、relay_log_recover参数值,以及master_auto_position的使用方式。
1,单线程模式的复制
当基于gtid模式复制的时候,并且设置了master_auto_posion参数和relay_log_recover=0,使用该设置,其中relay_log_info_repository和其他变量的设置都不会影响恢复。
当基于传统模式复制的情况下,需要设置relay_log_recovery=1和relay_log_info_repository=table。
2,多线程模式的复制
当基于gtid模式复制的时候,并且设置了master_auto_position和relay_log_recover=0,使用该配置,其relay_log_info_repository和其他变量的设置都会影响恢复。
当基于传统模式复制的时候,请设置relay_log_recover=1,sync_relay_log=1和relay_log_info_repository=table。
现在从节点查看slave_relay_log_info然后做记录。
[root@master ~]# kubectl exec -it pod/mysql-1 -n mysql -c mysql -- bash
1 mysql> select * from slave_relay_log_info\G 2 *************************** 1. row *************************** 3 Number_of_lines: 11 4 Relay_log_name: ./mysql-1-relay-bin.000002 5 Relay_log_pos: 204 6 Master_log_name: mysql-0-bin.000004 7 Master_log_pos: 155 8 Sql_delay: 0 9 Number_of_workers: 0 10 Id: 1 11 Channel_name: 12 Privilege_checks_username: NULL 13 Privilege_checks_hostname: NULL 14 Require_row_format: 0 15 1 row in set (0.00 sec)
查看尾从节点的slave_relay_log_info然后再次做记录。
[root@master ~]# kubectl exec -it pod/mysql-2 -n mysql -c mysql -- bash
1 mysql> select * from slave_relay_log_info\G 2 *************************** 1. row *************************** 3 Number_of_lines: 11 4 Relay_log_name: ./mysql-1-relay-bin.000002 5 Relay_log_pos: 204 6 Master_log_name: mysql-0-bin.000004 7 Master_log_pos: 155 8 Sql_delay: 0 9 Number_of_workers: 0 10 Id: 1 11 Channel_name: 12 Privilege_checks_username: NULL 13 Privilege_checks_hostname: NULL 14 Require_row_format: 0 15 1 row in set (0.00 sec)
查看正常之后的。
[root@master ~]# kubectl exec -it pod/mysql-2 -n mysql -c mysql -- bash
1 mysql> select * from slave_relay_log_info\G 2 *************************** 1. row *************************** 3 Number_of_lines: 11 4 Relay_log_name: ./mysql-2-relay-bin.000007 5 Relay_log_pos: 373 6 Master_log_name: mysql-0-bin.000004 7 Master_log_pos: 155 8 Sql_delay: 0 9 Number_of_workers: 0 10 Id: 1 11 Channel_name: 12 Privilege_checks_username: NULL 13 Privilege_checks_hostname: NULL 14 Require_row_format: 0 15 1 row in set (0.00 sec)
附上sts完整yaml代码
1 apiVersion: apps/v1 2 kind: StatefulSet 3 metadata: 4 name: mysql 5 namespace: mysql 6 spec: 7 replicas: 3 8 selector: 9 matchLabels: 10 app: mysql 11 serviceName: mysql 12 template: 13 metadata: 14 labels: 15 app: mysql 16 spec: 17 initContainers: 18 - name: init-mysql 19 image: mysql:8.0.19 20 imagePullPolicy: IfNotPresent 21 command: 22 - bash 23 - "-c" 24 - | 25 set -ex 26 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 27 myindex=${BASH_REMATCH[1]} 28 echo [mysqld] > /mnt/conf.d/server-id.cnf 29 echo server-id=$((100 + ${myindex})) >> /mnt/conf.d/server-id.cnf 30 if [[ ${myindex} -eq 0 ]]; then 31 cp /mnt/config-map/master.cnf /mnt/conf.d/ 32 else 33 cp /mnt/config-map/slave.cnf /mnt/conf.d/ 34 fi 35 volumeMounts: 36 - name: conf 37 mountPath: /mnt/conf.d 38 - name: config-map 39 mountPath: /mnt/config-map 40 - name: clone-mysql 41 image: mzmuer/xtrabackup:1.0 42 imagePullPolicy: IfNotPresent 43 command: 44 - bash 45 - "-c" 46 - | 47 set -ex 48 [[ -d /var/lib/mysql/mysql ]] && exit 0 49 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 50 myindex=${BASH_REMATCH[1]} 51 [[ ${myindex} -eq 0 ]] && exit 0 52 ncat --recv-only mysql-$((${myindex}-1)).mysql 3307 | xbstream -x -C /var/lib/mysql 53 xtrabackup --prepare --target-dir=/var/lib/mysql 54 # --redo-only 加了会导致为提交的事务不回滚 55 volumeMounts: 56 - name: data 57 mountPath: /var/lib/mysql 58 subPath: mysql 59 - name: conf 60 mountPath: /etc/mysql/conf.d 61 containers: 62 - name: mysql 63 image: mysql:8.0.19 64 imagePullPolicy: IfNotPresent 65 args: ["--default-authentication-plugin=mysql_native_password"] 66 env: 67 - name: MYSQL_ALLOW_EMPTY_PASSWORD 68 value: "1" 69 ports: 70 - name: mysql 71 containerPort: 3306 72 volumeMounts: 73 - name: data 74 mountPath: /var/lib/mysql 75 subPath: mysql 76 - name: conf 77 mountPath: /etc/mysql/conf.d 78 resources: 79 requests: 80 cpu: 250m 81 memory: 256Mi 82 limits: 83 cpu: 500m 84 memory: 512Mi 85 livenessProbe: 86 exec: 87 command: ["mysqladmin", "ping"] 88 initialDelaySeconds: 30 89 periodSeconds: 10 90 timeoutSeconds: 5 91 readinessProbe: 92 exec: 93 command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"] 94 initialDelaySeconds: 5 95 periodSeconds: 2 96 timeoutSeconds: 1 97 - name: xtrabackup 98 image: mzmuer/xtrabackup:1.0 99 imagePullPolicy: IfNotPresent 100 ports: 101 - name: xtrabackup 102 containerPort: 3307 103 command: 104 - bash 105 - "-c" 106 - | 107 set -ex 108 mkdir /test 109 cd /var/lib/mysql 110 if [[ -s xtrabackup_slave_info ]]; then 111 mv xtrabackup_slave_info change_master_to.sql.in 112 rm -f xtrabackup_binlog_info 113 elif [[ -f xtrabackup_binlog_info ]]; then 114 [[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1 115 echo -e "CHANGE MASTER TO\nMASTER_LOG_FILE=‘${BASH_REMATCH[1]}‘,\nMASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in 116 rm -f xtrabackup_binlog_info 117 fi 118 if [[ -f change_master_to.sql.in ]]; then 119 echo "Waiting for mysqld to be ready (accepting connections)" 120 until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done 121 echo "Initializing replication from clone position" 122 mv change_master_to.sql.in change_master_to.sql.orig 123 mysql -h 127.0.0.1 <<EOF 124 $(<change_master_to.sql.orig), 125 MASTER_HOST=‘mysql-0.mysql‘, 126 MASTER_USER=‘repl‘, 127 MASTER_PASSWORD=‘repl123.‘, 128 MASTER_CONNECT_RETRY=10; 129 START SLAVE; 130 EOF 131 echo "master slave config ok" 132 fi 133 [[ `hostname` =~ -([0-9]+)$ ]] || exit 1 134 myindex=${BASH_REMATCH[1]} 135 if [[ ${myindex} -eq 0 ]]; then 136 mysql -h 127.0.0.1 <<EOF 137 use mysql; 138 delete from user where user=‘repl‘ and host=‘%‘;flush privileges; 139 CREATE USER ‘repl‘@‘%‘ IDENTIFIED WITH mysql_native_password BY ‘repl123.‘; 140 GRANT REPLICATION SLAVE ON *.* TO ‘repl‘@‘%‘;flush privileges; 141 SELECT Host, User, plugin from mysql.user; 142 EOF 143 else 144 Slave_healthy=`mysql -h 127.0.0.1 -e ‘show slave status\G‘ 2> /dev/null |grep -E "Slave_IO_Running|Slave_SQL_Running"|awk ‘{print $2}‘|grep -c Yes` 145 if [[ ${Slave_healthy} -eq 2 ]]; then 146 echo "master slave healthy ok" 147 elif [[ ${Slave_healthy} -eq 1 ]]; then 148 echo "master slave healthy no" 149 mysql -h 127.0.0.1 <<EOF 150 stop slave; 151 reset slave; 152 start slave; 153 EOF 154 echo "master slave healthy revert" 155 elif [[ ${Slave_healthy} -eq 0 ]]; then 156 echo "master slave healthy no" 157 mysql -h 127.0.0.1 <<EOF 158 reset slave; 159 start slave; 160 EOF 161 echo "master slave healthy revert" 162 fi 163 fi 164 exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c 165 "xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root" 166 volumeMounts: 167 - name: data 168 mountPath: /var/lib/mysql 169 subPath: mysql 170 - name: conf 171 mountPath: /etc/mysql/conf.d 172 resources: 173 requests: 174 cpu: 100m 175 memory: 100Mi 176 limits: 177 cpu: 200m 178 memory: 200Mi 179 volumes: 180 - name: conf 181 emptyDir: {} 182 - name: config-map 183 configMap: 184 name: mysql 185 volumeClaimTemplates: 186 - metadata: 187 name: data 188 spec: 189 storageClassName: "managed-nfs-storage" 190 accessModes: ["ReadWriteMany"] 191 resources: 192 requests: 193 storage: 10Gi
作者:K& ,如需转载请附上原文链接,感谢。