上接Corosync+Pacemaker+MySQL+DRBD(一)http://9124573.blog.51cto.com/9114573/1768076
⑶布署corosync+pacemaker
◆安装软件包
pacemaker依赖corosync,安装pacemaker包会连带安装corosync包
yum -y install pacemaker
[root@node2 ~]# yum -y install pacemaker;ssh root@node1 'yum -y install pacemaker' ... Dependency Installed: clusterlib.x86_64 0:3.0.12.1-73.el6_7.2 corosync.x86_64 0:1.4.7-2.el6 corosynclib.x86_64 0:1.4.7-2.el6 libibverbs.x86_64 0:1.1.8-4.el6 ... [root@node2 ~]# rpm -ql corosync /etc/corosync /etc/corosync/corosync.conf.example #配置文件模板 /etc/corosync/corosync.conf.example.udpu /etc/corosync/service.d /etc/corosync/uidgid.d /etc/dbus-1/system.d/corosync-signals.conf /etc/rc.d/init.d/corosync #服务脚本 /etc/rc.d/init.d/corosync-notifyd /etc/sysconfig/corosync-notifyd /usr/bin/corosync-blackbox /usr/libexec/lcrso /usr/libexec/lcrso/coroparse.lcrso ... /usr/sbin/corosync /usr/sbin/corosync-cfgtool /usr/sbin/corosync-cpgtool /usr/sbin/corosync-fplay /usr/sbin/corosync-keygen #生成节点间通信时用到的认证密钥文件,默认从/dev/random读随机数 /usr/sbin/corosync-notifyd /usr/sbin/corosync-objctl /usr/sbin/corosync-pload /usr/sbin/corosync-quorumtool /usr/share/doc/corosync-1.4.7 ... /var/lib/corosync /var/log/cluster #日志文件目录
◆安装crmsh
RHEL自6.4起不再提供集群的命令行配置工具crmsh,默认提供的是pcs;本例中使用crmsh,crmsh依赖于pssh,因此需要一并下载安装
[root@node2 ~]# yum -y install pssh-2.3.1-2.el6.x86_64.rpm crmsh-1.2.6-4.el6.x86_64.rpm ... Installed: crmsh.x86_64 0:1.2.6-4.el6 pssh.x86_64 0:2.3.1-2.el6 Dependency Installed: python-dateutil.noarch 0:1.4.1-6.el6 redhat-rpm-config.noarch 0:9.0.3-44.el6.centos Complete!
◆配置corosync
cd /etc/corosync/
cp corosync.conf.example corosync.conf
vim corosync.conf,在其中加入:
service { #以插件化方式调用pacemaker
ver: 0
name: pacemaker
# use_mgmtd: yes
}
[root@node2 ~]# cd /etc/corosync/ [root@node2 corosync]# cp corosync.conf.example corosync.conf [root@node2 corosync]# vim corosync.conf # Please read the corosync.conf.5 manual page compatibility: whitetank totem { version: 2 secauth: on #是否进行消息认证;若启用,使用corosync-keygen生成密钥文件 threads: 0 interface { ringnumber: 0 bindnetaddr: 192.168.30.0 #接口绑定的网络地址 mcastaddr: 239.255.10.1 #传递心跳信息所使用的组播地址 mcastport: 5405 ttl: 1 } } logging { fileline: off to_stderr: no to_logfile: yes logfile: /var/log/cluster/corosync.log #日志路径 to_syslog: no debug: off timestamp: on #是否记录时间戳;当日志量很大时关闭该项可提高性能 logger_subsys { subsys: AMF debug: off } } #下面这段表示以插件的方式调用pacemaker service { ver: 0 name: pacemaker # use_mgmtd: yes }
◆生成节点间通信时用到的认证密钥文件
corosync-keygen
[root@node2 corosync]# corosync-keygen Corosync Cluster Engine Authentication key generator. Gathering 1024 bits for key from /dev/random. Press keys on your keyboard to generate entropy. Writing corosync key to /etc/corosync/authkey. [root@node2 corosync]# ll authkey -r-------- 1 root root 128 Apr 27 23:31 authkey
◆将配置文件和密钥文件同步到对方节点
scp -p authkey corosync.conf root@node1:/etc/corosync/
[root@node2 corosync]# scp -p authkey corosync.conf root@node1:/etc/corosync/ authkey 100% 128 0.1KB/s 00:00 corosync.conf 100% 2723 2.7KB/s 00:00
◆启动corosync
service corosync start
查看corosync引擎是否正常启动,是否正常读取配置文件:
grep -e "Corosync Cluster Engine" -e "configuration file" /var/log/cluster/corosync.log
查看初始化成员节点通知是否正常发出:
grep TOTEM /var/log/cluster/corosync.log
检查启动过程中是否有错误产生:
grep ERROR: /var/log/cluster/corosync.log | grep -v unpack_resources
查看pacemaker是否正常启动:
grep pcmk_startup /var/log/cluster/corosync.log
[root@node2 ~]# service corosync start;ssh root@node1 'service corosync start' Starting Corosync Cluster Engine (corosync): [ OK ] Starting Corosync Cluster Engine (corosync): [ OK ] [root@node2 ~]# grep -e "Corosync Cluster Engine" -e "configuration file" /var/log/cluster/corosync.log Apr 28 02:03:08 corosync [MAIN ] Corosync Cluster Engine ('1.4.7'): started and ready to provide service. Apr 28 02:03:08 corosync [MAIN ] Successfully read main configuration file '/etc/corosync/corosync.conf'. [root@node2 ~]# grep TOTEM /var/log/cluster/corosync.log Apr 28 02:03:08 corosync [TOTEM ] Initializing transport (UDP/IP Multicast). Apr 28 02:03:08 corosync [TOTEM ] Initializing transmit/receive security: libtomcrypt SOBER128/SHA1HMAC (mode 0). Apr 28 02:03:08 corosync [TOTEM ] The network interface [192.168.30.20] is now up. Apr 28 02:03:08 corosync [TOTEM ] A processor joined or left the membership and a new membership was formed. Apr 28 02:03:11 corosync [TOTEM ] A processor joined or left the membership and a new membership was formed. Apr 28 02:04:10 corosync [TOTEM ] A processor joined or left the membership and a new membership was formed. [root@node2 ~]# grep ERROR: /var/log/cluster/corosync.log | grep -v unpack_resources #以下错误提示可忽略 Apr 28 02:03:08 corosync [pcmk ] ERROR: process_ais_conf: You have configured a cluster using the Pacemaker plugin for Corosync. The plugin is not supported in this environment and will be removed very soon. Apr 28 02:03:08 corosync [pcmk ] ERROR: process_ais_conf: Please see Chapter 8 of 'Clusters from Scratch' (http://www.clusterlabs.org/doc) for details on using Pacemaker with CMAN Apr 28 02:03:13 corosync [pcmk ] ERROR: pcmk_wait_dispatch: Child process cib terminated with signal 11 (pid=7953, core=true) ... [root@node2 ~]# grep pcmk_startup /var/log/cluster/corosync.log Apr 28 02:03:08 corosync [pcmk ] info: pcmk_startup: CRM: Initialized Apr 28 02:03:08 corosync [pcmk ] Logging: Initialized pcmk_startup Apr 28 02:03:08 corosync [pcmk ] info: pcmk_startup: Maximum core file size is: 18446744073709551615 Apr 28 02:03:08 corosync [pcmk ] info: pcmk_startup: Service: 9 Apr 28 02:03:08 corosync [pcmk ] info: pcmk_startup: Local hostname: node2
◆配置接口crmsh的启动命令是crm,其使用方式有两种:
命令行模式,例如 # crm ra list ocf
交互式模式,例如:
# crm
crm(live)# ra
crm(live)ra# list ocf
或者:
# crm
crm(live)# ra list ocf
help:查看帮助信息
end/cd:切回上一级
exit/quit:退出程序
常用子命令:
①status: 查看集群状态
②resource:
start, stop, restart
promote/demote:提升/降级一个主从资源
cleanup:清理资源状态
migrate:将资源迁移到另外一个节点上
③configure:
primitive, group, clone, ms/master(主从资源)
具体用法可使用help命令查看,如crm(live)configure# help primitive
示例:
primitive webstore ocf:Filesystem params device=172.16.100.6:/web/htdocs directory=/var/www/html fstype=nfs op monitor interval=20s timeout=30s
group webservice webip webserver
location, collocation, order
示例:
colocation webserver_with_webip inf: webserver webip
order webip_before_webserver mandatory: webip webserver #mandatory也可换成inf
location webip_on_node2 webip rule inf: #uname eq node2
或location webip_on_node2 webip inf: node2
monitor #pacemaker具有监控资源的功能
monitor
例如:monitor webip 30s:20s
very:CIB语法验证
commit:将更改后的信息提交写入CIB(集群信息库)
注意:配置完后要记得very和commit
show:显示CIB对象
edit:直接以vim模式编辑CIB对象
refresh:重新读取CIB信息
delete:删除CIB对象
erase:擦除所有配置
④node:
standby:让节点离线,强制其成为备节点
online:让节点重新上线
fence:隔离节点
clearstate:清理节点状态信息
delete:删除一个节点
⑤ra:
classes:查看资源代理有哪些种类
有四种:lsb, ocf, service, stonith
list
例如:
list ocf #列出ocf类型的资源代理
list ocf linbit #列出ocf类型中,由linbit提供的资源代理
meta/info [
例如:info ocf:linbit:drbd
或 info ocf:drbd
或 info drbd
providers
例如:providers apache
crm(live)# help #查看有哪些子命令或获取帮助信息 This is crm shell, a Pacemaker command line interface. Available commands: cib manage shadow CIBs resource resources management #资源管理 configure CRM cluster configuration #集群配置 node nodes management #节点管理 options user preferences history CRM cluster history site Geo-cluster support ra resource agents information center #资源代理信息 status show cluster status #显示集群状态 help,? show help (help topics for list of topics) end,cd,up go back one level quit,bye,exit exit the program #退出 crm(live)# status #查看集群状态 Last updated: Fri Apr 29 00:19:36 2016 Last change: Thu Apr 28 22:41:38 2016 Stack: classic openais (with plugin) Current DC: node2 - partition with quorum Version: 1.1.11-97629de 2 Nodes configured, 2 expected votes 0 Resources configured Online: [ node1 node2 ]
crm(live)# configure crm(live)configure# help ... Commands for resources are: #可配置的资源类型 - `primitive` - `monitor` - `group` - `clone` - `ms`/`master` (master-slave) In order to streamline large configurations, it is possible to define a template which can later be referenced in primitives: - `rsc_template` In that case the primitive inherits all attributes defined in the template. There are three types of constraints: #可定义的约束 - `location` - `colocation` - `order` ... crm(live)configure# help primitive #查看使用帮助 ... Usage: ............... primitive{[ :[ :]] |@} [params attr_list] [meta attr_list] [utilization attr_list] [operations id_spec] [op op_type [ = ...] ...] attr_list :: [$id= ] = [ = ...] | $id-ref= id_spec :: $id= | $id-ref= op_type :: start | stop | monitor ............... Example: ............... primitive apcfence stonith:apcsmart \ params ttydev=/dev/ttyS0 hostlist="node1 node2" \ op start timeout=60s \ op monitor interval=30m timeout=60s crm(live)configure# cd #使用cd或end命令切回上一级
crm(live)# ra crm(live)ra# help This level contains commands which show various information about the installed resource agents. It is available both at the top level and at the `configure` level. Available commands: classes list classes and providers list list RA for a class (and provider) meta show meta data for a RA providers show providers for a RA and a class help show help (help topics for list of topics) end go back one level quit exit the program crm(live)ra# classes lsb ocf / heartbeat linbit pacemaker service stonith crm(live)ra# help list List available resource agents for the given class. If the class is `ocf`, supply a provider to get agents which are available only from that provider. Usage: ............... list[ ] ............... Example: ............... list ocf pacemaker ............... crm(live)ra# list ocf CTDB ClusterMon Delay Dummy Filesystem ... ... crm(live)ra# list ocf linbit drbd crm(live)ra# help meta Show the meta-data of a resource agent type. This is where users can find information on how to use a resource agent. It is also possible to get information from some programs: `pengine`, `crmd`, `cib`, and `stonithd`. Just specify the program name instead of an RA. Usage: ............... info [ :[ :]] info [ ] (obsolete) ............... Example: ............... info apache info ocf:pacemaker:Dummy info stonith:ipmilan info pengine ............... crm(live)ra# info ocf:linbit:drbd ... Operations' defaults (advisory minimum): start timeout=240 promote timeout=90 demote timeout=90 notify timeout=90 stop timeout=100 monitor_Slave timeout=20 interval=20 monitor_Master timeout=20 interval=10 crm(live)ra# cd
crm(live)# resource crm(live)resource# help At this level resources may be managed. All (or almost all) commands are implemented with the CRM tools such as `crm_resource(8)`. Available commands: status show status of resources start start a resource stop stop a resource restart restart a resource promote promote a master-slave resource demote demote a master-slave resource ... crm(live)resource# help cleanup Cleanup resource status. Typically done after the resource has temporarily failed. If a node is omitted, cleanup on all nodes. If there are many nodes, the command may take a while. Usage: ............... cleanup[ ] ...............
⊙在使用crmsh配置集群时曾遇到过如下错误:
ERROR: CIB not supported: validator 'pacemaker-2.0', release '3.0.9'
ERROR: You may try the upgrade command
大概的意思就是:经检验器pacemaker-2.0检查后发现crm shell版本相对较低,不被CIB(集群信息库)支持,因此建议更新crmsh版本;
其实如果我们执行 cibadmin --query | grep validate 就可看到这条信息:
为解决此问题,可尝试另一个办法,将检验器的版本降低: cibadmin --modify --xml-text ' 经测试,使用此方法后故障解除 ⑷配置高可用集群 ◆配置集群工作属性 本例中只有两个节点,没有stonith设备和仲裁设备,而corosync默认启用了stonith。启用stonith而又没有配置相应的stonith设备时,corosync是不允许资源启动的,通过以下命令就可得知: crm_verify -L -V 因此,我们需要做如下设定: crm configure property stonith-enabled=false crm configure property no-quorum-policy=ignore ◆配置集群资源 mysqld和drbd是我们要定义的集群服务,先要确保两个节点上的服务停止且不会开机自动启动: service mysqld stop;chkconfig mysqld off service drbd stop;chkconfig drbd off drbd需要同时运行在两个节点上,且一个节点是Master,另一个节点为Slave(primary/secondary模型);因此,要将其配置为主从资源(特殊的克隆资源),且要求服务刚启动时两个节点都处于slave状态 drbd的RA目前由OCF归类为linbit,其路径为/usr/lib/ocf/resource.d/linbit/drbd ⊕配置资源: primitive myip ocf:heartbeat:IPaddr params ip=192.168.30.100 op monitor interval=30s timeout=20s 主从资源是从一个主资源克隆而来,所以要先配置一个主资源 ms表示配置主从资源,ms_mydrbd为主从资源的名称,后面的mydrbd表示要克隆的资源 clone-max:在集群中最多能运行多少份克隆资源,默认和集群中的节点数相同; clone-node-max:每个节点上最多能运行多少份克隆资源,默认是1; notify:当成功启动或关闭一份克隆资源,要不要通知给其它的克隆资源,默认是true primitive mystore ocf:heartbeat:Filesystem params device=/dev/drbd0 directory=/mydata fstype=ext4 op monitor interval=20s timeout=60s op start timeout=60s op stop timeout=60s ⊕定义约束: group myservice myip mystore myserver 存储设备需要跟随drbd的主节点,且只能在drbd服务将该节点提升为主节点后才可启动 ⊕stickness 资源在节点间每一次的来回流动都会造成那段时间内其无法正常被访问,所以,我们有时候需要在资源因为节点故障转移到其它节点后,即便原来的节点恢复正常也禁止资源再次流转回来。这可以通过定义资源的黏性(stickiness)来实现 stickness取值范围: 0:默认值,资源放置在系统中的最适合位置 大于0:值越高表示资源越愿意留在当前位置 小于0:绝对值越高表示资源越愿意离开当前位置 INFINITY:如果不是因节点不适合运行资源(节点关机、节点待机、达到migration-threshold 或配置更改)而强制资源转移,资源总是留在当前位置 -INFINITY 可以通过以下方式为资源指定默认黏性值: crm configure rsc_defaults resource-stickiness=100 模拟故障 模拟资源转移
[root@node2 ~]# crm_verify -L -V
error: unpack_resources: Resource start-up disabled since no STONITH resources have been defined
error: unpack_resources: Either configure some or disable STONITH with the stonith-enabled option
error: unpack_resources: NOTE: Clusters with shared data need STONITH to ensure data integrity
Errors found during check: config not valid
[root@node2 ~]# crm configure property stonith-enabled=false
[root@node2 ~]# crm configure property no-quorum-policy=ignore
[root@node2 ~]# crm configure show
node node1
node node2
property $id="cib-bootstrap-options" \
dc-version="1.1.11-97629de" \
cluster-infrastructure="classic openais (with plugin)" \
expected-quorum-votes="2" \
stonith-enabled="false" \
no-quorum-policy="ignore"
[root@node2 ~]# crm_verify -L -V
[root@node2 ~]#
primitive mydrbd ocf:linbit:drbd params drbd_resource=mysql op monitor role=Master interval=10s timeout=20s op monitor role=Slave interval=20s timeout=30s op start timeout=240s op stop timeout=100s
ms ms_mydrbd mydrbd meta master-max=1 master-node-max=1 clone-max=2 clone-node-max=1[ notify=True]
primitive myserver lsb:mysqld op monitor interval=20s timeout=20s
collocation mystore_with_ms_mydrbd_master inf: mystore ms_mydrbd:Master
order mystore_after_ms_mydrbd_master mandatory: ms_mydrbd:promote mystore
order myserver_after_mystore mandatory: mystore myserver
order myserver_after_myip inf: myip myserver#准备工作
[root@node2 ~]# service mysqld stop
Stopping mysqld: [ OK ]
[root@node2 ~]# umount /mydata
[root@node2 ~]# drbdadm secondary mysql
[root@node2 ~]# cat /proc/drbd
version: 8.4.3 (api:1/proto:86-101)
GIT-hash: 89a294209144b68adb3ee85a73221f964d3ee515 build by gardner@, 2013-11-29 12:28:00
0: cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate C r-----
ns:124 nr:0 dw:2282332 dr:4213545 al:7 bm:396 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0
[root@node2 ~]# service drbd stop;ssh root@node1 'service drbd stop'
Stopping all DRBD resources: .
Stopping all DRBD resources: .
[root@node2 ~]# chkconfig mysqld off;ssh root@node1 'chkconfig mysqld off'
[root@node2 ~]# chkconfig drbd off;ssh root@node1 'chkconfig drbd off'
#配置资源
crm(live)configure# primitive myip ocf:heartbeat:IPaddr params ip=192.168.30.100 op monitor interval=30s timeout=20s
crm(live)configure# primitive mydrbd ocf:linbit:drbd params drbd_resource=mysql op monitor role=Master interval=10s timeout=20s op monitor role=Slave interval=20s timeout=30s op start timeout=240s op stop timeout=100s
crm(live)configure# ms ms_mydrbd mydrbd meta master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 notify=True
crm(live)configure# primitive mystore ocf:heartbeat:Filesystem params device=/dev/drbd0 directory=/mydata fstype=ext4 op monitor interval=20s timeout=60s op start timeout=60s op stop timeout=60s
crm(live)configure# primitive myserver lsb:mysqld op monitor interval=20s timeout=20s
#定义约束
crm(live)configure# group myservice myip mystore myserver
crm(live)configure# collocation mystore_with_ms_mydrbd_master inf: mystore ms_mydrbd:Master
crm(live)configure# order mystore_after_ms_mydrbd_master mandatory: ms_mydrbd:promote mystore
crm(live)configure# order myserver_after_mystore mandatory: mystore myserver
crm(live)configure# order myserver_after_myip inf: myip myserver
crm(live)configure# verify #语法验证
crm(live)configure# commit #提交配置
crm(live)configure# show #查看配置信息
node node1
node node2
primitive mydrbd ocf:linbit:drbd \
params drbd_resource="mysql" \
op monitor role="Master" interval="10s" timeout="20s" \
op monitor role="Slave" interval="20s" timeout="30s" \
op start timeout="240s" interval="0" \
op stop timeout="100s" interval="0"
primitive myip ocf:heartbeat:IPaddr \
params ip="192.168.30.100" \
op monitor interval="20s" timeout="30s"
primitive myserver lsb:mysqld \
op monitor interval="20s" timeout="20s"
primitive mystore ocf:heartbeat:Filesystem \
params device="/dev/drbd0" directory="/mydata" fstype="ext4" \
op monitor interval="20s" timeout="60s" \
op start timeout="60s" interval="0" \
op stop timeout="60s" interval="0"
group myservice myip mystore myserver
ms ms_mydrbd mydrbd \
meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="True"
colocation mystore_with_ms_mydrbd_master inf: mystore ms_mydrbd:Master
order myserver_after_myip inf: myip myserver
order myserver_after_mystore inf: mystore myserver
order mystore_after_ms_mydrbd_master inf: ms_mydrbd:promote mystore
property $id="cib-bootstrap-options" \
dc-version="1.1.11-97629de" \
cluster-infrastructure="classic openais (with plugin)" \
expected-quorum-votes="2" \
stonith-enabled="false" \
no-quorum-policy="ignore"
crm(live)configure# cd
crm(live)# status #查看集群状态
Last updated: Fri Apr 29 13:43:06 2016
Last change: Fri Apr 29 13:42:23 2016
Stack: classic openais (with plugin)
Current DC: node2 - partition with quorum
Version: 1.1.11-97629de
2 Nodes configured, 2 expected votes
5 Resources configured
Online: [ node1 node2 ] #node1和node2均在线
Master/Slave Set: ms_mydrbd [mydrbd]
Masters: [ node1 ] #node1为mydrbd资源的主节点
Slaves: [ node2 ]
Resource Group: myservice #组中的各资源均正常启动
myip (ocf::heartbeat:IPaddr): Started node1
mystore (ocf::heartbeat:Filesystem): Started node1
myserver (lsb:mysqld): Started node1
#验证
[root@node1 ~]# ip addr show #使用ip addr查看配置的新的ip
...
2: eth0:
[root@node1 ~]# service mysqld stop #手动停止mysqld服务
Stopping mysqld: [ OK ]
[root@node1 ~]# crm status
...
Online: [ node1 node2 ]
Master/Slave Set: ms_mydrbd [mydrbd]
Masters: [ node1 ]
Slaves: [ node2 ]
Resource Group: myservice
myip (ocf::heartbeat:IPaddr): Started node1
mystore (ocf::heartbeat:Filesystem): Started node1
myserver (lsb:mysqld): Started node1
Failed actions:
myserver_monitor_20000 on node1 'not running' (7): call=70, status=complete, last-rc-change='Fri Apr 29 23:00:55 2016', queued=0ms, exec=0ms
#因为我们有监控资源,当pacemaker发现资源状态异常时,会尝试重新启动资源,若启动失败会尝试转移到对方节点
[root@node1 ~]# service mysqld status #可以看到服务已自动重新启动
mysqld (pid 4783) is running...
crm(live)# node standby #强制资源转移
crm(live)# status
...
Node node1: standby
Online: [ node2 ]
Master/Slave Set: ms_mydrbd [mydrbd]
Slaves: [ node1 node2 ]
Resource Group: myservice
myip (ocf::heartbeat:IPaddr): Started node2
mystore (ocf::heartbeat:Filesystem): FAILED node2
myserver (lsb:mysqld): Stopped
Failed actions: #显示有错误信息
mystore_start_0 on node2 'unknown error' (1): call=236, status=complete, last-rc-change='Fri Apr 29 15:45:17 2016', queued=0ms, exec=69ms
mystore_start_0 on node2 'unknown error' (1): call=236, status=complete, last-rc-change='Fri Apr 29 15:45:17 2016', queued=0ms, exec=69ms
crm(live)# resource cleanup mystore #清理资源mystore的状态
Cleaning up mystore on node1
Cleaning up mystore on node2
Waiting for 2 replies from the CRMd.. OK
crm(live)# status #恢复正常,可以看到资源已成功转移至node2
...
Node node1: standby
Online: [ node2 ]
Master/Slave Set: ms_mydrbd [mydrbd]
Masters: [ node2 ]
Stopped: [ node1 ]
Resource Group: myservice
myip (ocf::heartbeat:IPaddr): Started node2
mystore (ocf::heartbeat:Filesystem): Started node2
myserver (lsb:mysqld): Started node2
crm(live)# node online #让node1重新上线
#验证
[root@node2 ~]# ip addr show
...
2: eth0: