前言
换了下基础镜像，从centos7换成alpine3； 结果由于内核不同导致shell命令的展示也不同； 代码里原来的自动获取ip 与java 进程的shell直接失灵
遂写了一套兼容的写法， 可以避免由于系统不同导致的兼容问题
获取本地IP
centos7写法（原）
ifconfig
[root@5a64c59344fd tmp]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1450
inet 10.0.65.125 netmask 255.255.255.0 broadcast 10.0.65.255
ether 02:42:0a:00:41:7d txqueuelen 0 (Ethernet)
RX packets 1857219 bytes 1869596677 (1.7 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1625531 bytes 755588840 (720.5 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.18.0.10 netmask 255.255.0.0 broadcast 172.18.255.255
ether 02:42:ac:12:00:0a txqueuelen 0 (Ethernet)
RX packets 3071823 bytes 3818583903 (3.5 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3901239 bytes 1999734532 (1.8 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1000 (Local Loopback)
RX packets 646986 bytes 49083885 (46.8 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 646986 bytes 49083885 (46.8 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@5a64c59344fd tmp]#
原shell
SERVICE_IP=$(ifconfig | grep "inet" | awk -F "[: ]+" '{print $3}' | head -n1)
这里用 {print $3} 写死了， 用在这个结构下没有问题
alpine3写法
ifconfig
k8s-test-fileservice-7fd5756b46-k5mpj:/# ifconfig
eth0 Link encap:Ethernet HWaddr E6:FB:E7:59:56:2A
inet addr:172.22.0.121 Bcast:0.0.0.0 Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:85901 errors:0 dropped:0 overruns:0 frame:0
TX packets:77105 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:8412465 (8.0 MiB) TX bytes:7646501 (7.2 MiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:11228 errors:0 dropped:0 overruns:0 frame:0
TX packets:11228 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:561400 (548.2 KiB) TX bytes:561400 (548.2 KiB)
k8s-test-fileservice-7fd5756b46-k5mpj:/#
inet addr:172.22.0.121 这一行多了一个addr: 用原命令得改成print $4；如果基础镜像又切回centos7那么shell也得跟着改， 所以最好有一个兼容的写法
兼容写法
SERVICE_IP=$(ifconfig eth0|awk '{if($0~"inet") {print $0}}'| grep -oE '[0-9]+.[0-9]+.[0-9]+.[0-9]+'|head -n1)
获取java进程号
centos7写法（原）
ps -ef
[root@5a64c59344fd tmp]# ps -ef
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 Feb25 ? 00:00:00 /bin/bash /home/start_java.sh microservice-file
root 7 1 0 Feb25 ? 00:00:27 sh /home/memory_log.sh
root 8 1 0 Feb25 ? 01:58:48 java -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/tmp/ -Xmx4096m -XX:MaxDirectMemorySize=2g -jar /tmp/micro
root 330 0 0 Mar03 pts/1 00:00:00 bash
root 831 0 0 17:31 pts/6 00:00:00 bash
root 1334 7 0 17:41 ? 00:00:00 vmstat 5 10
root 1335 831 0 17:41 pts/6 00:00:00 ps -ef
root 2968 0 0 Feb28 pts/0 00:00:00 bash
root 10685 0 0 09:39 pts/5 00:00:00 bash
root 12798 0 0 Mar07 pts/3 00:00:00 bash
root 20904 0 0 Mar03 pts/2 00:00:00 bash
root 30540 0 0 Mar17 pts/4 00:00:00 bash
原shell
ps -ef | grep java |grep microservice | grep "spring.profiles.active" | awk '{print $2}'
alpine3写法
ps -ef
k8s-test-fileservice-7fd5756b46-k5mpj:/# ps -ef
PID USER TIME COMMAND
1 root 0:00 {start_java.sh} /bin/bash /home/start_java.sh microservice-file
7 root 1:58 java -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/tmp/ -Xmx3072m -jar /tmp/microservice-file.jar --spring.profiles.active=test -Dthumbnailator.conserv
7763 root 0:00 bash
10478 root 0:00 ps -ef
k8s-test-fileservice-7fd5756b46-k5mpj:/#
这里的PID 变到第一列了
兼容写法
ps -ef | awk 'NR==1 {for(i=1;i<=NF;i++) if ($i=="PID") {pid_col=i}} NR>1 {if($0!~"ps -ef | awk" && $0~"microservice" && $0~"spring.profiles.active") {print $pid_col}}'