Eu gostaria de isolar processos usando lxc-execute. É possível definir largura de banda, CPU e limite de memória?
Dei uma olhada no homem do lxc.conf, mas não o achei exaustivo.
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Antes de tudo, gostaria que você entendesse os Cgroups que fazem parte do utilitário LXC. quando você tiver um contêiner, obviamente desejaria garantir que os vários contêineres em execução passassem fome de qualquer outro contêiner ou processo dentro dele. Com isso em mente, o cara legal do projeto LXCaka Daniel Lezcano integrou cgroups com a tecnologia de contêineres que ele estava criando, ou seja, LXC. Agora, se você deseja atribuir o uso de recursos, precisará configurar o CGROUP. Os Cgroups permitem alocar recursos - como tempo de CPU, memória do sistema, largura de banda da rede ou combinações desses recursos - entre grupos de tarefas (processos) definidos pelo usuário em execução em um sistema. Você pode monitorar os cgroups configurados, negar acesso aos cgroups a determinados recursos e até reconfigurar seus cgroups dinamicamente em um sistema em execução. O serviço cgconfig (configuração do grupo de controle) pode ser configurado para iniciar no momento da inicialização e restabelecer seus cgroups predefinidos, tornando-os persistentes durante as reinicializações. Os grupos de grupos podem ter várias hierarquias porque cada hierarquia é anexada a um ou mais subsistemas (também conhecidos como controladores ou controladores de recursos). Isso criará várias árvores que não estão conectadas. Existem nove subsistemas disponíveis.
Podemos listar os subsistemas que temos em nosso kernel pelo comando:
lssubsys –am
O lxc-cgroup obtém ou define o valor do grupo de controle associado ao nome do contêiner. Gerencie o grupo de controle associado a um contêiner. exemplo de uso:
lxc-cgroup -n foo cpuset.cpus "0,3"
atribua os processadores 0 e 3 ao contêiner.
Agora, em minha opinião, respondi sua pergunta original. Mas deixe-me adicionar um pouco dos parâmetros que podem ser úteis para você configurar seu contêiner para usar o lxc. existem formas condensadas da documentação de controle de recursos pela redhat
Parâmetros Modificáveis BLKIO:
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
Parâmetros modificáveis do CFS:
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.
Parâmetros modificáveis de RT:
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.
CPUset:
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.
Dispositivos:
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
Memória:
O subsistema de memória gera relatórios automáticos sobre os recursos de memória usados pelas tarefas em um cgroup e define limites para o uso da memória por essas tarefas Parâmetros modificáveis pela memória: memory.limit_in_bytes: define a quantidade máxima de memória do usuário. pode usar sufixos como K para quilo e M para mega etc. Isso limita apenas os grupos mais baixos na hierarquia. ou seja, o cgroup raiz não pode ser limitado memory.memsw.limit_in_bytes: define a quantidade máxima para a soma da memória e uso de swap. Novamente, isso não pode limitar o cgroup raiz.
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:
O subsistema net_cls identifica os pacotes de rede com um identificador de classe (classid) que permite ao controlador de tráfego Linux (tc) identificar pacotes originados de um cgroup específico. O controlador de tráfego pode ser configurado para atribuir prioridades diferentes a pacotes de diferentes 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:
O subsistema de prioridade da rede (net_prio) fornece uma maneira de definir dinamicamente a prioridade do tráfego de rede por cada interface de rede para aplicativos em vários cgroups. A prioridade de uma rede é um número atribuído ao tráfego de rede e usado internamente pelo sistema e pelos dispositivos de rede. A prioridade de rede é usada para diferenciar pacotes enviados, enfileirados ou descartados. O controlador de tráfego (tc) é responsável por definir a prioridade das redes.
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
Este documento é bastante útil: http://doc.opensuse.org/documentation/html/openSUSE/opensuse-tuning/cha.tuning.cgroups.html
As informações estão na documentação do kernel Linux aqui: / usr / src / linux / Documentation / cgroups