使用 lxc-execute 限制内存和 CPU

Question

我想使用 lxc-execute 隔离进程。是否可以设置带宽、CPU 和内存限制？

我查看了 lxc.conf 的人，但我没有发现它详尽无遗。

Answer 1

首先，我想你理解的cgroup属于LXC工具的一部分。当您拥有一个容器时，您显然希望确保您运行的各种容器都已完成，从而使其中的任何其他容器或进程处于饥饿状态。考虑到这一点，这个好人 LXC 项目的又名 Daniel Lezcano 将 cgroups 与他正在创建的容器技术（即 LXC）集成在一起。现在，如果要分配资源使用情况，则需要考虑配置 CGROUP。Cgroup 允许您在系统上运行的用户定义的任务（进程）组之间分配资源，例如 CPU 时间、系统内存、网络带宽或这些资源的组合。您可以监控您配置的 cgroup，拒绝 cgroup 访问某些资源，甚至可以在正在运行的系统上动态重新配置您的 cgroup。cgconfig（控制组配置）服务可以配置为在引导时启动并重新建立预定义的 cgroup，从而使它们在重新启动后保持不变。Cgroups 可以有多个层次结构，因为每个层次结构都附加到一个或多个子系统（也称为资源控制器或控制器）。这将创建多个未连接的树。有九个子系统可用。

1. blkio 对块设备上的输入/输出访问设置限制
2. 用于 cgroup 任务访问 CPU 的 cpu 调度程序
3. cpuacct 为 CPU 使用和 cgroup 生成报告
4. cpuset 将 CPU 和内存分配给 cgroup
5. 设备按任务管理对设备的访问
6. 冷冻机暂停/恢复任务
7. 内存限制内存
8. net_cls 标记网络数据包以允许 Linux 流量控制器识别任务流量
9. ns 命名空间

我们可以通过以下命令列出内核中的子系统：

lssubsys –am

lxc-cgroup 从与容器名称关联的控制组中获取或设置值。管理与容器关联的控制组。用法示例：

lxc-cgroup -n foo cpuset.cpus "0,3" 

将处理器 0 和 3 分配给容器。

现在，我认为我已经回答了你原来的问题。但是让我添加一些可能对您配置容器以使用 lxc 有用的参数。有redhat的资源控制文档的精简形式

BLKIO 可修改参数：

    blkio.reset_stats : any int to reset the statistics of BLKIO
    blkio.weight : 100 - 1000 (relative proportion of block I/O access)
    blkio.weight_device : major, minor , weight 100 - 1000 
    blkio.time : major, minor and time (device type and node numbers and length of access in milli seconds)
    blkio.throttle.read_bps_device : major, minor specifies the upper limit on the number of read operations a device can perform. The rate of the read operations is specified in bytes per second.
    blkio.throttle.read_iops_device :major, minor and operations_per_second specifies the upper limit on the number of read operations a device can  perform
    blkio.throttle.write_bps_device : major, minor and bytes_per_second (bytes per second)
    blkio.throttle.write_iops_device : major, minor and operations_per_second

CFS 可修改参数：

    cpu.cfs_period_us : specifies a period of time in microseconds for how regularly a cgroup's access to CPU resources should be reallocated. If tasks in a cgroup should be able to access a single CPU for 0.2 seconds out of every 1 second, set cpu.cfs_quota_us to 200000 and cpu.cfs_period_us to 1000000.
    cpu.cfs_quota_us : total amount of time in microseconds that all tasks in a cgroup can run during one period. Once limit has reached, they are not allowed to run beyond that. 
    cpu.shares : contains an integer value that specifies the relative share of CPU time available to tasks in a cgroup.


    Note: For example, tasks in two cgroups that have cpu.shares set to 1 will receive equal CPU time, but tasks in a cgroup that has cpu.shares set to 2 receive twice the CPU time of tasks in a cgroup where cpu.shares is set to 1. Note that shares of CPU time are distributed per CPU. If one cgroup is limited to 25% of CPU and another cgroup is limited to 75% of CPU, on a multi-core system, both cgroups will use 100% of two different CPUs. 

RT 可修改参数：

cpu.rt_period_us : time in microseconds for how regularly a cgroups access to CPU resources should be reallocated. 
cpu.rt_runtime_us : same as above.

中央处理器：

cpuset subsystem assigns individual CPUs and memory nodes to cgroups.
Note: here some parameters are mandatory
Mandatory: 


cpuset.cpus : specifies the CPUs that tasks in this cgroup are permitted to access. This is a comma-separated list in ASCII format, with dashes (" -")                 to represent ranges. For example 0-2,16 represents CPUs 0, 1, 2, and 16. 
        cpuset.mems : specifies the memory nodes that tasks in this cgroup are permitted to access. same as above format


Optional: 
        cpuset.cpu_exclusive : contains a flag ( 0 or 1) that specifies whether cpusets other than this one and its parents and children can share the CPUs specified for this cpuset. By default ( 0), CPUs are not allocated exclusively to one cpuset. 
        cpuset.mem_exclusive : contains a flag ( 0 or 1) that specifies whether other cpusets can share the memory nodes specified for this cpuset. By default ( 0), memory nodes are not allocated exclusively to one cpuset. Reserving memory nodes for the exclusive use of a cpuset ( 1) is functionally the same as enabling a memory hardwall with the cpuset.mem_hardwall parameter.
        cpuset.mem_hardwall : contains a flag ( 0 or 1) that specifies whether kernel allocations of memory page and buffer data should be restricted to the memory nodes specified for this cpuset. By default ( 0), page and buffer data is shared across processes belonging to multiple users. With a hardwall enabled ( 1), each tasks' user allocation can be kept separate.
        cpuset.memory_pressure_enabled : contains a flag ( 0 or 1) that specifies whether the system should compute the memory pressure created by the processes in this cgroup
        cpuset.memory_spread_page : contains a flag ( 0 or 1) that specifies whether file system buffers should be spread evenly across the memory nodes allocated to this cpuset. By default ( 0), no attempt is made to spread memory pages for these buffers evenly, and buffers are placed on the same node on which the process that created them is running. 
        cpuset.memory_spread_slab : contains a flag ( 0 or 1) that specifies whether kernel slab caches for file input/output operations should be spread evenly across the cpuset. By default ( 0), no attempt is made to spread kernel slab caches evenly, and slab caches are placed on the same node on which the process that created them is running.
        cpuset.sched_load_balance : contains a flag ( 0 or 1) that specifies whether the kernel will balance loads across the CPUs in this cpuset. By default ( 1), the kernel balances loads by moving processes from overloaded CPUs to less heavily used CPUs.

设备：

The devices subsystem allows or denies access to devices by tasks in a cgroup. 
    devices.allow : specifies devices to which tasks in a cgroup have access. Each entry has four fields: type, major, minor, and access.
    type can be of following three values: 
        a - applies to all devices
        b - block devices
        c - character devices
    access is a sequence of one or more letters: 
        r read from device
        w write to device
        m create device files that do not yet exist

    devices.deny : similar syntax as above
    devices.list : reports devices for which access control has been set for tasks in this cgroup

记忆：

The memory subsystem generates automatic reports on memory resources used by the tasks in a cgroup, and sets limits on memory use by those tasks Memory modifiable parameters: memory.limit_in_bytes : sets the maximum amount of user memory. can use suffixes like K for kilo and M for mega etc. This only limits the groups lower in the heirarchy. i.e. root cgroup cannot be limited memory.memsw.limit_in_bytes : sets the maximum amount for the sum of memory and swap usage. again this cannot limit the root cgroup.

    Note: memory.limit_in_bytes should always be set before memory.memsw.limit_in_bytes because only after limit, can swp limit be set
    memory.force_empty : when set to 0, empties memory of all pages used by tasks in this cgroup
    memory.swappiness : sets the tendency of the kernel to swap out process memory used by tasks in this cgroup instead of reclaiming pages from the page cache. he default value is 60. Values lower than 60 decrease the kernel's tendency to swap out process memory, values greater than 60 increase the kernel's tendency to swap out process memory, and values greater than 100 permit the kernel to swap out pages that are part of the address space of the processes in this cgroup. 


    Note: Swappiness can only be asssigned to leaf groups in the cgroups architecture. i.e if any cgroup has a child cgroup, we cannot set the swappiness for that
    memory.oom_control : contains a flag ( 0 or 1) that enables or disables the Out of Memory killer for a cgroup. If enabled ( 0), tasks that attempt to consume more memory than they are allowed are immediately killed by the OOM killer. 

net_cls:

The net_cls subsystem tags network packets with a class identifier (classid) that allows the Linux traffic controller ( tc) to identify packets originating from a particular cgroup. The traffic controller can be configured to assign different priorities to packets from different cgroups.

net_cls.classid : 0XAAAABBBB AAAA = major number (hex)
                         BBBB = minor number (hex)
        net_cls.classid contains a single value that indicates a traffic control handle. The value of classid read from the net_cls.classid file is presented in the decimal format while the value to be written to the file is expected in the hexadecimal format. e.g. 0X100001 = 10:1

net_prio :

网络优先级 (net_prio) 子系统提供了一种为各种 cgroup 中的应用程序动态设置每个网络接口的网络流量优先级的方法。网络的优先级是分配给网络流量并由系统和网络设备在内部使用的数字。网络优先级用于区分发送、排队或丢弃的数据包。流量控制器 (tc) 负责设置网络优先级。

net_prio.ifpriomap : networkinterface , priority (/cgroup/net_prio/iscsi/net_prio.ifpriomap)
        Contents of the net_prio.ifpriomap file can be modified by echoing a string into the file using the above format, for example:

            ~]# echo "eth0 5" > /cgroup/net_prio/iscsi/net_prio.ifpriomap