cgroup与docker
1、使用 cgroup namespace 需要内核开启 CONFIG_CGROUPS 选项。可通过以下方式验证：
1 root@container:~/namespace_test# grep CONFIG_CGROUPS /boot/config-$(uname -r)
2、查看cgroup挂载信息：
root@lord:~# mount -t cgroup cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,name=systemd) cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct) cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids) cgroup on /sys/fs/cgroup/rdma type cgroup (rw,nosuid,nodev,noexec,relatime,rdma) cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset) cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb) cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event) cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer) cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices) cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio) cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio) cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
可以看到cgroup位置在 /sys/fs/cgroup/
root@lord:~# ls -l /sys/fs/cgroup/ total 0 dr-xr-xr-x 4 root root 0 Oct 12 10:32 blkio lrwxrwxrwx 1 root root 11 Oct 12 10:32 cpu -> cpu,cpuacct lrwxrwxrwx 1 root root 11 Oct 12 10:32 cpuacct -> cpu,cpuacct dr-xr-xr-x 5 root root 0 Oct 12 10:32 cpu,cpuacct dr-xr-xr-x 3 root root 0 Oct 12 10:32 cpuset dr-xr-xr-x 5 root root 0 Oct 12 10:32 devices dr-xr-xr-x 5 root root 0 Oct 12 10:32 freezer dr-xr-xr-x 3 root root 0 Oct 12 10:32 hugetlb dr-xr-xr-x 5 root root 0 Oct 12 10:32 memory lrwxrwxrwx 1 root root 16 Oct 12 10:32 net_cls -> net_cls,net_prio dr-xr-xr-x 3 root root 0 Oct 12 10:32 net_cls,net_prio lrwxrwxrwx 1 root root 16 Oct 12 10:32 net_prio -> net_cls,net_prio dr-xr-xr-x 3 root root 0 Oct 12 10:32 perf_event dr-xr-xr-x 4 root root 0 Oct 12 10:32 pids dr-xr-xr-x 3 root root 0 Oct 12 10:32 rdma dr-xr-xr-x 5 root root 0 Oct 12 10:32 systemd dr-xr-xr-x 5 root root 0 Oct 12 10:32 unified
root@lord:/sys/fs/cgroup/cpu# pwd /sys/fs/cgroup/cpu
root@lord:/sys/fs/cgroup/cpu# ls -l
dr-xr-xr-x 5 root root 0 Oct 12 10:32 ./ drwxr-xr-x 15 root root 380 Oct 12 10:32 ../ drwxr-xr-x 2 root root 0 Oct 12 17:22 aa/ -rw-r--r-- 1 root root 0 Oct 12 17:22 cgroup.clone_children -rw-r--r-- 1 root root 0 Oct 12 17:22 cgroup.procs -r--r--r-- 1 root root 0 Oct 12 17:22 cgroup.sane_behavior -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.stat -rw-r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_all -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_percpu -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_percpu_sys -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_percpu_user -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_sys -r--r--r-- 1 root root 0 Oct 12 17:22 cpuacct.usage_user -rw-r--r-- 1 root root 0 Oct 12 17:22 cpu.cfs_period_us -rw-r--r-- 1 root root 0 Oct 12 17:22 cpu.cfs_quota_us -rw-r--r-- 1 root root 0 Oct 12 17:22 cpu.shares -r--r--r-- 1 root root 0 Oct 12 17:22 cpu.stat -rw-r--r-- 1 root root 0 Oct 12 17:22 notify_on_release -rw-r--r-- 1 root root 0 Oct 12 17:22 release_agent drwxr-xr-x 99 root root 0 Oct 12 10:32 system.slice/ -rw-r--r-- 1 root root 0 Oct 12 17:22 tasks drwxr-xr-x 2 root root 0 Oct 12 17:22 user.slice/
4.查看当前进程所关联的cgroup
root@lord:~# cat /proc/$$/cgroup 12:memory:/user.slice/user-0.slice/session-19.scope 11:net_cls,net_prio:/ 10:blkio:/user.slice 9:devices:/user.slice 8:freezer:/ 7:perf_event:/ 6:hugetlb:/ 5:cpuset:/ 4:rdma:/ 3:pids:/user.slice/user-0.slice/session-19.scope 2:cpu,cpuacct:/user.slice 1:name=systemd:/user.slice/user-0.slice/session-19.scope 0::/user.slice/user-0.slice/session-19.scope
根目录就是上面查询的cgroup挂载信息： 如 5:cpuset:/ 关联 /sys/fs/cgroup/cpu
5.新增子cgroup，如新增CPU下的cgroup,并将当前进程加入tasks
写入tasks的进程 将受该cgroup的资源限制
root@lord:/sys/fs/cgroup/cpu# mkdir test root@lord:/sys/fs/cgroup/cpu# ls -l test/ total 0 -rw-r--r-- 1 root root 0 Oct 12 17:57 cgroup.clone_children -rw-r--r-- 1 root root 0 Oct 12 17:57 cgroup.procs -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.stat -rw-r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_all -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_percpu -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_percpu_sys -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_percpu_user -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_sys -r--r--r-- 1 root root 0 Oct 12 17:57 cpuacct.usage_user -rw-r--r-- 1 root root 0 Oct 12 17:57 cpu.cfs_period_us -rw-r--r-- 1 root root 0 Oct 12 17:57 cpu.cfs_quota_us -rw-r--r-- 1 root root 0 Oct 12 17:57 cpu.shares -r--r--r-- 1 root root 0 Oct 12 17:57 cpu.stat -rw-r--r-- 1 root root 0 Oct 12 17:57 cpu.uclamp.max -rw-r--r-- 1 root root 0 Oct 12 17:57 cpu.uclamp.min -rw-r--r-- 1 root root 0 Oct 12 17:57 notify_on_release -rw-r--r-- 1 root root 0 Oct 12 17:57 tasks root@lord:/sys/fs/cgroup/cpu# cd test;echo $$ >> tasks root@lord:/sys/fs/cgroup/cpu#
现在可以通过更改test目录下的配置文件，设置进程组使用的CPU限制
6：docker进程与cgroup
root@lord:/sys/fs/cgroup/cpu/test# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f197f2487e5f alpine-tinghua "sh -c 'tail -f /dev…" 7 hours ago Up 7 hours bb
root@lord:/sys/fs/cgroup/cpu/test# docker inspect --format '{{.State.Pid}}' bb #查看容器在主机的进程号
11290
root@lord:/sys/fs/cgroup/cpu/test# cat /proc/11290/cgroup
12:memory:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
11:net_cls,net_prio:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
10:blkio:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
9:devices:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
8:freezer:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
7:perf_event:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
6:hugetlb:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
5:cpuset:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
4:rdma:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
3:pids:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
2:cpu,cpuacct:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
1:name=systemd:/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
0::/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope
root@lord:/sys/fs/cgroup/cpu/test#
root@lord:/sys/fs/cgroup/cpu/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope# pwd /sys/fs/cgroup/cpu/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope root@lord:/sys/fs/cgroup/cpu/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope# ll total 0 drwxr-xr-x 2 root root 0 Oct 12 11:03 ./ drwxr-xr-x 99 root root 0 Oct 12 10:32 ../ -rw-r--r-- 1 root root 0 Oct 12 18:07 cgroup.clone_children -rw-r--r-- 1 root root 0 Oct 12 18:07 cgroup.procs -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.stat -rw-r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_all -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_percpu -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_percpu_sys -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_percpu_user -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_sys -r--r--r-- 1 root root 0 Oct 12 18:07 cpuacct.usage_user -rw-r--r-- 1 root root 0 Oct 12 18:07 cpu.cfs_period_us -rw-r--r-- 1 root root 0 Oct 12 18:07 cpu.cfs_quota_us -rw-r--r-- 1 root root 0 Oct 12 18:07 cpu.shares -r--r--r-- 1 root root 0 Oct 12 18:07 cpu.stat -rw-r--r-- 1 root root 0 Oct 12 18:07 cpu.uclamp.max -rw-r--r-- 1 root root 0 Oct 12 18:07 cpu.uclamp.min -rw-r--r-- 1 root root 0 Oct 12 18:07 notify_on_release -rw-r--r-- 1 root root 0 Oct 12 18:07 tasks root@lord:/sys/fs/cgroup/cpu/system.slice/docker-f197f2487e5f40c0468ba6b76f1d9cf451304d2ee10ef8266b75e8e6f6554bd7.scope#
当我们创建容器时传入的资源限制：如内存或者cpu 都会通过写入cgroup文件 实现资源限制
