Folks,
I saw this commit today and thought I would use this opportunity to remind
everyone the obvious: documentation is usually the first thing a
user—especially a new user—sees when they start evaluating Mesos. As with
everything, first impression is utterly important. Please strive to make
our docs *consistent* and *consumable*. ESLs please seek support of a
native speaker.
Alex.
On 6 December 2016 at 00:05, wrote:
> Repository: mesos
> Updated Branches:
> refs/heads/master 814ed3f8e -> 134a6a5ce
>
>
> Added documentation for posix/rlimit isolator.
>
> Review: https://reviews.apache.org/r/53982/
>
>
> Project: http://git-wip-us.apache.org/repos/asf/mesos/repo
> Commit: http://git-wip-us.apache.org/repos/asf/mesos/commit/134a6a5c
> Tree: http://git-wip-us.apache.org/repos/asf/mesos/tree/134a6a5c
> Diff: http://git-wip-us.apache.org/repos/asf/mesos/diff/134a6a5c
>
> Branch: refs/heads/master
> Commit: 134a6a5cea2af260fee870c8aea2667d60077946
> Parents: 814ed3f
> Author: Benjamin Bannier
> Authored: Mon Dec 5 15:04:59 2016 -0800
> Committer: Jie Yu
> Committed: Mon Dec 5 15:04:59 2016 -0800
>
> --
> docs/mesos-containerizer.md | 6 +++
> docs/posix_rlimits.md | 88
> 2 files changed, 94 insertions(+)
> --
>
>
> http://git-wip-us.apache.org/repos/asf/mesos/blob/134a6a5c/
> docs/mesos-containerizer.md
> --
> diff --git a/docs/mesos-containerizer.md b/docs/mesos-containerizer.md
> index 6d13b2d..d0b9d76 100644
> --- a/docs/mesos-containerizer.md
> +++ b/docs/mesos-containerizer.md
> @@ -295,6 +295,12 @@ destroyed.
>
> This is described in a [separate document](cni.md).
>
> +
> ### The `linux/capabilities` Isolator
>
> This is described in a [separate document](linux_capabilities.md).
> +
> +
> +### The `posix/rlimits` Isolator
> +
> +This is described in a [separate document](posix_rlimits.md).
>
> http://git-wip-us.apache.org/repos/asf/mesos/blob/134a6a5c/
> docs/posix_rlimits.md
> --
> diff --git a/docs/posix_rlimits.md b/docs/posix_rlimits.md
> new file mode 100644
> index 000..0a0e6a8
> --- /dev/null
> +++ b/docs/posix_rlimits.md
> @@ -0,0 +1,88 @@
> +# POSIX Resource Limits Support in Mesos Containerizer
> +
> +This document describes the `posix/rlimits` isolator. The isolator adds
> support
> +for setting POSIX resource limits (rlimits) for containers launched using
> the
> +[Mesos containerizer](mesos-containerizer.md).
> +
> +POSIX rlimits can be used control the resources a process can consume.
> Resource
> +limits are typically set at boot time and inherited when a child process
> is
> +forked from a parent process; resource limits can also be modified via
> +`setrlimit(2)`. In many interactive shells, resource limits can be
> inspected or
> +modified with the `ulimit` shell built-in.
> +
> +A POSIX resource limit consist of a _soft_ and a _hard_ limit. The soft
> limit
> +specifies the effective resource limit for the current and forked
> process, while
> +the hard limit gives the value up to which processes may increase their
> +effective limit; increasing the hard limit is a privileged action. It is
> +required that the soft limit is less than or equal to the hard limit.
> +System administrators can use a hard resource limit to define the maximum
> amount
> +of resources that can be consumed by a user; users can employ soft
> resource
> +limits to ensure that one of their tasks only consumes a limited amount
> of the
> +global hard resource limit.
> +
> +This isolator permits setting per-task resource limits. This isolator
> interprets
> +rlimits specified as part of a task's `ContainerInfo` for the Mesos
> +containerizer, e.g.,
> +```{.json}
> +{
> + "container": {
> +"type": "MESOS",
> +"rlimit_info": {
> + "rlimits": [
> +{
> + "type": "RLMT_CORE"
> +},
> +{
> + "type": "RLMT_STACK",
> + "soft": 8192,
> + "hard": 32768
> +}
> + ]
> +}
> + }
> +}
> +```
> +
> +To enable interpretation of rlimits, agents need to
> +be started with `posix/rlimits` in its `--isolation` flag, e.g.,
> +
> +```{.console}
> +mesos-agent --master= --ip=
> + --work_dir=/var/lib/mesos
> + --isolation=posix/rlimits[,other isolation flags]
> +```
> +
> +To set a hard limit for a task larger than the current value of the hard
> limit,
> +the agent process needs to be under a privileged user (with the
> +`CAP_SYS_RESOURCE` capability), typically `root`.
> +
> +POSIX currently defines a base set of resources, see
> +[the documentation](http://pubs.opengroup.org/onlinepubs/
> 009695399/functions/getrlimit.html);
> +Linux defines additional resource limits, see e.g., the documentation of
> +`setrlimit(2)
