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support for detecting if inside docker container.
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@paulczar
paulczar committed Oct 12, 2014
1 parent 8ea4bf3 commit ffe3a9e
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Showing 2 changed files with 139 additions and 24 deletions.
14 changes: 11 additions & 3 deletions lib/ohai/plugins/linux/virtualization.rb
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,10 @@ def lxc_version_exists?
which('lxc-version')
end

def docker_exists?
which('docker')
end

collect_data(:linux) do
virtualization Mash.new unless virtualization
virtualization[:systems] = Mash.new unless virtualization[:systems]
Expand Down Expand Up @@ -170,9 +174,9 @@ def lxc_version_exists?
# Kernel docs, https://www.kernel.org/doc/Documentation/cgroups
if File.exists?("/proc/self/cgroup")
if File.read("/proc/self/cgroup") =~ %r{^\d+:[^:]+:/(lxc|docker)/.+$}
virtualization[:system] = "lxc"
virtualization[:system] = $1
virtualization[:role] = "guest"
virtualization[:systems][:lxc] = "guest"
virtualization[:systems][$1.to_sym] = "guest"
elsif lxc_version_exists? && File.read("/proc/self/cgroup") =~ %r{\d:[^:]+:/$}
# lxc-version shouldn't be installed by default
# Even so, it is likely we are on an LXC capable host that is not being used as such
Expand All @@ -181,12 +185,16 @@ def lxc_version_exists?
virtualization[:system] = "lxc"
virtualization[:role] = "host"
end

# In general, the 'systems' framework from OHAI-182 is less susceptible to conflicts
# But, this could overwrite virtualization[:systems][:lxc] = "guest"
# If so, we may need to look further for a differentiator (OHAI-573)
virtualization[:systems][:lxc] = "host"
end
elsif File.exists?("/.dockerenv") || File.exists?("/.dockerinit")
virtualization[:system] = "docker"
virtualization[:role] = "guest"
virtualization[:systems][:docker] = "guest"
end

end
end
149 changes: 128 additions & 21 deletions spec/unit/plugins/linux/virtualization_spec.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,8 @@
File.stub(:exists?).with("/proc/bc/0").and_return(false)
File.stub(:exists?).with("/proc/vz").and_return(false)
File.stub(:exists?).with("/proc/self/cgroup").and_return(false)
File.stub(:exists?).with("/.dockerenv").and_return(false)
File.stub(:exists?).with("/.dockerinit").and_return(false)
end

describe "when we are checking for xen" do
Expand Down Expand Up @@ -320,27 +322,6 @@
@plugin[:virtualization][:systems][:lxc].should == "guest"
end

it "should set lxc guest if /proc/self/cgroup exist and there are /docker/<name> mounts" do
self_cgroup=<<-CGROUP
11:hugetlb:/
10:perf_event:/
9:blkio:/
8:net_cls:/
7:freezer:/
6:devices:/
5:memory:/
4:cpuacct,cpu:/docker/9c2adaa4c391ec0d3bf994fbd91ff30c3d317694d179e5b1dc7e1e4c8ed56b61
3:cpuset:/
2:name=systemd:/system.slice/docker.service
CGROUP
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(true)
File.stub(:read).with("/proc/self/cgroup").and_return(self_cgroup)
@plugin.run
@plugin[:virtualization][:system].should == "lxc"
@plugin[:virtualization][:role].should == "guest"
@plugin[:virtualization][:systems][:lxc].should == "guest"
end

it "should set not set anything if /proc/self/cgroup exist and the cgroup is named arbitrarily, it isn't necessarily lxc." do
self_cgroup=<<-CGROUP
8:blkio:/Charlie
Expand Down Expand Up @@ -409,8 +390,134 @@
end
end

describe "when we are checking for docker" do
it "should set docker guest if /proc/self/cgroup exist and there are /docker/<hexadecimal> mounts" do
self_cgroup=<<-CGROUP
8:blkio:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
7:net_cls:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
6:freezer:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
5:devices:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
4:memory:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
3:cpuacct:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
2:cpu:/docker/baa660ed81bc81d262ac6e19486142aeec5fce2043e2a173eb2505c6fbed89bc
1:cpuset:/
CGROUP
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(true)
File.stub(:read).with("/proc/self/cgroup").and_return(self_cgroup)
@plugin.run
@plugin[:virtualization][:system].should == "docker"
@plugin[:virtualization][:role].should == "guest"
@plugin[:virtualization][:systems][:docker].should == "guest"
end

it "should set docker guest if /proc/self/cgroup exist and there are /docker/<name> mounts" do
self_cgroup=<<-CGROUP
8:blkio:/docker/vanilla
7:net_cls:/docker/vanilla
6:freezer:/docker/vanilla
5:devices:/docker/vanilla
4:memory:/docker/vanilla
3:cpuacct:/docker/vanilla
2:cpu:/docker/vanilla
1:cpuset:/docker/vanilla
CGROUP
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(true)
File.stub(:read).with("/proc/self/cgroup").and_return(self_cgroup)
@plugin.run
@plugin[:virtualization][:system].should == "docker"
@plugin[:virtualization][:role].should == "guest"
@plugin[:virtualization][:systems][:docker].should == "guest"
end

it "should set not set anything if /proc/self/cgroup exist and the cgroup is named arbitrarily, it isn't necessarily lxc." do
self_cgroup=<<-CGROUP
8:blkio:/Charlie
7:net_cls:/Charlie
6:freezer:/Charlie
5:devices:/Charlie
4:memory:/Charlie
3:cpuacct:/Charlie
2:cpu:/Charlie
1:cpuset:/Charlie
CGROUP
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(true)
File.stub(:read).with("/proc/self/cgroup").and_return(self_cgroup)
@plugin.run
@plugin[:virtualization].should == {'systems' => {}}
end

context "/proc/self/cgroup only has / mounts" do
before(:each) do
self_cgroup=<<-CGROUP
8:blkio:/
7:net_cls:/
6:freezer:/
5:devices:/
4:memory:/
3:cpuacct:/
2:cpu:/
1:cpuset:/
CGROUP
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(true)
File.stub(:read).with("/proc/self/cgroup").and_return(self_cgroup)
@plugin.run
@plugin[:virtualization].should == {'systems' => {}}
end

end

it "does not set the old virtualization attributes if they are already set" do
@plugin.stub(:docker_exists?).and_return("/usr/bin/docker")
@plugin[:virtualization] = Mash.new
@plugin[:virtualization][:system] = "the cloud"
@plugin[:virtualization][:role] = "cumulonimbus"
@plugin.run
@plugin[:virtualization][:system].should_not == "docker"
@plugin[:virtualization][:role].should_not == "host"
end

it "does not set docker host if docker does not exist" do
@plugin.stub(:docker_exists?).and_return(false)
@plugin.run
@plugin[:virtualization][:system].should be_nil
@plugin[:virtualization][:role].should be_nil
@plugin[:virtualization].should == {'systems' => {}}
end

it "should not set virtualization if /proc/self/cgroup isn't there" do
File.should_receive(:exists?).with("/proc/self/cgroup").and_return(false)
@plugin.run
@plugin[:virtualization].should == {'systems' => {}}
end

it "should set virtualization if /.dockerenv exists" do
File.should_receive(:exists?).with("/.dockerenv").and_return(true)
@plugin.run
@plugin[:virtualization][:system].should == "docker"
@plugin[:virtualization][:role].should == "guest"
@plugin[:virtualization][:systems][:docker].should == "guest"
end

it "should set virtualization if /.dockerinit exists" do
File.should_receive(:exists?).with("/.dockerinit").and_return(true)
@plugin.run
@plugin[:virtualization][:system].should == "docker"
@plugin[:virtualization][:role].should == "guest"
@plugin[:virtualization][:systems][:docker].should == "guest"
end

it "should not set virtualization if /.dockerenv or /.dockerinit doesn't exists" do
File.should_receive(:exists?).with("/.dockerenv").and_return(false)
File.should_receive(:exists?).with("/.dockerinit").and_return(false)
@plugin.run
@plugin[:virtualization].should == {'systems' => {}}
end

end

it "should not set virtualization if no tests match" do
@plugin.run
@plugin[:virtualization].should == {'systems' => {}}
end

end

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