详解Docker cpu限制分析

本文测试了，Docker容器限制cpu资源使用的几个配置参数。分别使用top和dstat命令分析了资源占有情况。

package mainimport (  "flag"  "runtime"  "fmt")func main() {  cpunum := flag.Int("cpunum", 0, "cpunum")  flag.Parse()  fmt.Println("cpunum:", *cpunum)  runtime.GOMAXPROCS(*cpunum)  for i := 0; i < *cpunum - 1; i++ {    go func() {      for {      }    }()  }  for {  }}

制作了一个测试cpu占用的镜像，镜像默认占满1个核心

FROM busyboxCOPY ./full_cpu /full_cpuRUN chmod +x /full_cpuENTRYPOINT ["/full_cpu", "-cpunum"]CMD ["1"]docker build -t fangfenghua/cpuuseset .docker push fangfenghua/cpuusesetdocker info...Default Runtime: runcSecurity Options: seccompKernel Version: 3.10.0-229.el7.x86_64Operating System: CentOS Linux 7 (Core)OSType: linuxArchitecture: x86_64CPUs: 4Total Memory: 993.3 MiBName: localhost.localdomainID: TU6M:E6WM:PZDN:ULJX:EWKS:   ...

docker run -it --rm=true fangfenghua/cpuuseset [root@localhost src]# toptop - 07:23:52 up 1:23, 2 users, load average: 0.61, 1.12, 1.04Tasks: 154 total,  3 running, 145 sleeping,  6 stopped,  0 zombie%Cpu(s): 18.0 us, 0.1 sy, 0.0 ni, 81.8 id, 0.0 wa, 0.0 hi, 0.1 si, 0.0 stKiB Mem : 1017144 total,  422120 free,  171676 used,  423348 buff/cacheKiB Swap: 1040380 total, 1040284 free,    96 used.  688188 avail Mem  PID USER   PR NI  VIRT  RES  SHR S %CPU %MEM   TIME+ COMMAND                                         20196 root   20  0  3048  720  460 R 101.7 0.1  0:37.56 full_cpu                                           1 root   20  0  41536  4028  2380 S  0.0 0.4  0:02.60 systemd                                           2 root   20  0    0   0   0 S  0.0 0.0  0:00.04 kthreadd                                           3 root   20  0    0   0   0 S  0.0 0.0  0:00.48 ksoftirqd/0                                         5 root    0 -20    0   0   0 S  0.0 0.0  0:00.00 kworker/0:0H                                         7 root   rt  0    0   0   0 S  0.0 0.0  0:00.69 migration/0  docker run -it --rm=true fangfenghua/cpuuseset 4top - 07:27:17 up 1:27, 2 users, load average: 2.41, 1.47, 1.18Tasks: 159 total,  3 running, 145 sleeping, 11 stopped,  0 zombie%Cpu(s): 99.6 us, 0.2 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.3 si, 0.0 stKiB Mem : 1017144 total,  402508 free,  190908 used,  423728 buff/cacheKiB Swap: 1040380 total, 1040284 free,    96 used.  668608 avail Mem  PID USER   PR NI  VIRT  RES  SHR S %CPU %MEM   TIME+ COMMAND                                         20935 root   20  0  3048  720  452 R 400.0 0.1  0:55.80 full_cpu                                           1 root   20  0  41620  4088  2380 S  0.0 0.4  0:02.88 systemd                                           2 root   20  0    0   0   0 S  0.0 0.0  0:00.04 kthreadd 

在Linux 系统上，可以用来限制docker容器资源占用的参数有：