cgroup resource

Use the cgroup Chef InSpec audit resource to test the different parameters values of the control group (cgroup) resource controllers. A cgroup is a Linux kernel feature that limits, accounts, and isolates the resource usage (such as CPU, memory, disk I/O, network) of a collection of processes.

Availability

Install

This resource is distributed with Chef InSpec.

Syntax

describe cgroup("CARROTKING") do
  its("cpuset.cpus") { should eq 0 }
end

where

• cpuset.cpus is a property of this resource and a parameter of the cpuset resource controller.
• CARROTKING is the name of cgroup directory.

Properties

• All parameters of the cgroup resource controller are valid properties of this resource. Some of them are: cpuset.cpus, memory.limit_in_bytes, memory.stat, freezer.state, cpu.stat, cpuacct.usage, pids.current, blkio.throttle.io_service_bytes.

Matchers

• For a full list of available matchers, refer matchers page.
• The matchers applicable for this resource are: eq, cmp, and match.

eq

eq tests whether the two values are of same data type and includes configuration entries that are numbers. It fails if the types do not match. Use cmp for less restrictive comparisons that ignores data type while comparing.

cmp

Unlike eq, cmp is a matcher for less-restrictive comparisons. This matcher attempts to fit the actual value to the comparing type and meant to relieve the user from having to write type-casts and resolutions.

match

match checks if a string matches a regular expression. Use match when the output of cgget -n -r [subsystem.parameters] [cgroup-name] is a multi-line output.

Examples

The following examples show how to use this Chef InSpec audit resource.

Example 1

Use eq to test for parameters that have a single line integer value. The value considered is the output obtained on cgget -n -r [subsystem.parameters] [cgroup-name].

describe cgroup("CARROTKING") do
  its("cpuset.cpus") { should eq 0 }
end

Example 2

Use cmp to test for parameters with less-restrictive comparisons and has a single line integer value. The value considered is the output obtained on cgget -n -r [subsystem.parameters] [cgroup-name].

describe cgroup("CARROTKING") do
  its("memory.limit_in_bytes") { should cmp 9223372036854771712 }
end

Example 3

Use match to test for parameters that have multi-line values and can be passed as regex. The value considered is the output obtained on cgget -n -r [subsystem.parameters] [cgroup-name].

describe cgroup("CARROTKING") do
  its("memory.stat") { should match /\bhierarchical_memory_limit 9223372036854771712\b/ }
end