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# Pacemaker Cluster Test Suite (CTS)
## Purpose
CTS thoroughly exercises a pacemaker test cluster by running a randomized
series of predefined tests on the cluster. CTS can be run against a
pre-existing cluster configuration or (more typically) overwrite the existing
configuration with a test configuration.
## Requirements
* Three or more machines (one test exerciser and two or more test cluster
machines).
* The test cluster machines should be on the same subnet and have journalling
filesystems (ext3, ext4, xfs, etc.) for all of their filesystems other than
/boot. You also need a number of free IP addresses on that subnet if you
intend to test mutual IP address takeover.
* The test exerciser machine doesn't need to be on the same subnet as the test
cluster machines. Minimal demands are made on the exerciser machine - it
just has to stay up during the tests.
* It helps a lot in tracking problems if all machines' clocks are closely
synchronized. NTP does this automatically, but you can do it by hand if you
want.
* The exerciser needs to be able to ssh over to the cluster nodes as root
without a password challenge. Configure ssh accordingly (see the Mini-HOWTO
at the end of this document for more details).
* The exerciser needs to be able to resolve the machine names of the
test cluster - either by DNS or by /etc/hosts.
* CTS is not guaranteed to run on all platforms that pacemaker itself does.
It calls commands such as service that may not be provided by all OSes.
## Preparation
Install Pacemaker (including CTS) on all machines. These scripts are
coordinated with particular versions of Pacemaker, so you need the same version
of CTS as the rest of Pacemaker, and you need the same version of
pacemaker and CTS on both the test exerciser and the test cluster machines.
You can install CTS from source, although many distributions provide
packages that include it (e.g. pacemaker-cts or pacemaker-dev).
Typically, packages will install CTS as /usr/share/pacemaker/tests/cts.
Configure cluster communications (Corosync, CMAN or Heartbeat) on the
cluster machines and verify everything works.
NOTE: Do not run the cluster on the test exerciser machine.
NOTE: Wherever machine names are mentioned in these configuration files,
they must match the machines' `uname -n` name. This may or may not match
the machines' FQDN (fully qualified domain name) - it depends on how
you (and your OS) have named the machines.
## Run CTS
Now assuming you did all this, what you need to do is run CTSlab.py:
python ./CTSlab.py [options] number-of-tests-to-run
You must specify which nodes are part of the cluster with --nodes, e.g.:
--node "pcmk-1 pcmk-2 pcmk-3"
Most people will want to save the output with --outputfile, e.g.:
--outputfile ~/cts.log
Unless you want to test your pre-existing cluster configuration, you also want:
--clobber-cib
--populate-resources
--test-ip-base $IP # e.g. --test-ip-base 192.168.9.100
and configure some sort of fencing:
--stonith $TYPE # e.g. "--stonith xvm" to use fence_xvm or "--stonith lha" to use external/ssh
A complete command line might look like:
python ./CTSlab.py --nodes "pcmk-1 pcmk-2 pcmk-3" --outputfile ~/cts.log \
--clobber-cib --populate-resources --test-ip-base 192.168.9.100 \
--stonith xvm 50
For more options, use the --help option.
NOTE: Perhaps more convenient way to compile a command line like above
is to use cluster_test script that, at least in the source repository,
sits in the same directory as this very file.
To extract the result of a particular test, run:
crm_report -T $test
## Optional/advanced testing
### Memory testing
Pacemaker and CTS have various options for testing memory management. On the
cluster nodes, pacemaker components will use various environment variables to
control these options. How these variables are set varies by OS, but usually
they are set in the /etc/sysconfig/pacemaker or /etc/default/pacemaker file.
Valgrind is a program for detecting memory management problems (such as
use-after-free errors). If you have valgrind installed, you can enable it by
setting the following environment variables on all cluster nodes:
PCMK_valgrind_enabled=attrd,cib,crmd,lrmd,pengine,stonith-ng
VALGRIND_OPTS="--leak-check=full --trace-children=no --num-callers=25
--log-file=/var/lib/pacemaker/valgrind-%p
--suppressions=/usr/share/pacemaker/tests/valgrind-pcmk.suppressions
--gen-suppressions=all"
and running CTS with these options:
--valgrind-tests --valgrind-procs="attrd cib crmd lrmd pengine stonith-ng"
These options should only be set while specifically testing memory management,
because they may slow down the cluster significantly, and they will disable
writes to the CIB. If desired, you can enable valgrind on a subset of pacemaker
components rather than all of them as listed above.
Valgrind will put a text file for each process in the location specified by
valgrind's --log-file option. For explanations of the messages valgrind
generates, see http://valgrind.org/docs/manual/mc-manual.html
Separately, if you are using the GNU C library, the G_SLICE, MALLOC_PERTURB_,
and MALLOC_CHECK_ environment variables can be set to affect the library's
memory management functions.
When using valgrind, G_SLICE should be set to "always-malloc", which helps
valgrind track memory by always using the malloc() and free() routines
directly. When not using valgrind, G_SLICE can be left unset, or set to
"debug-blocks", which enables the C library to catch many memory errors
but may impact performance.
If the MALLOC_PERTURB_ environment variable is set to an 8-bit integer, the C
library will initialize all newly allocated bytes of memory to the integer
value, and will set all newly freed bytes of memory to the bitwise inverse of
the integer value. This helps catch uses of uninitialized or freed memory
blocks that might otherwise go unnoticed. Example:
MALLOC_PERTURB_=221
If the MALLOC_CHECK_ environment variable is set, the C library will check for
certain heap corruption errors. The most useful value in testing is 3, which
will cause the library to print a message to stderr and abort execution.
Example:
MALLOC_CHECK_=3
Valgrind should be enabled for either all nodes or none, but the C library
variables may be set differently on different nodes.
### Remote node testing
If the pacemaker_remoted daemon is installed on all cluster nodes, CTS will
enable remote node tests.
The remote node tests choose a random node, stop the cluster on it, start
pacemaker_remote on it, and add an ocf:pacemaker:remote resource to turn it
into a remote node. When the test is done, CTS will turn the node back into
a cluster node.
To avoid conflicts, CTS will rename the node, prefixing the original node name
with "remote-". For example, "pcmk-1" will become "remote-pcmk-1".
The name change may require special stonith configuration, if the fence agent
expects the node name to be the same as its hostname. A common approach is to
specify the "remote-" names in pcmk_host_list. If you use pcmk_host_list=all,
CTS will expand that to all cluster nodes and their "remote-" names.
You may additionally need a pcmk_host_map argument to map the "remote-" names
to the hostnames. Example:
--stonith xvm --stonith-args \
pcmk_arg_map=domain:uname,pcmk_host_list=all,pcmk_host_map=remote-pcmk-1:pcmk-1;remote-pcmk-2:pcmk-2
### Remote node testing with valgrind
When running the remote node tests, the pacemaker components on the cluster
nodes can be run under valgrind as described in the "Memory testing" section.
However, pacemaker_remote cannot be run under valgrind that way, because it is
started by the OS's regular boot system and not by pacemaker.
Details vary by system, but the goal is to set the VALGRIND_OPTS environment
variable and then start pacemaker_remoted by prefixing it with the path to
valgrind.
The init script and systemd service file provided with pacemaker_remote will
load the pacemaker environment variables from the same location used by other
pacemaker components, so VALGRIND_OPTS will be set correctly if using one of
those.
For an OS using systemd, you can override the ExecStart parameter to run
valgrind. For example:
mkdir /etc/systemd/system/pacemaker_remote.service.d
cat >/etc/systemd/system/pacemaker_remote.service.d/valgrind.conf <<EOF
[Service]
ExecStart=
ExecStart=/usr/bin/valgrind /usr/sbin/pacemaker_remoted
EOF
### Container testing
If the --container-tests option is given to CTS, it will enable
testing of LXC resources (currently only the RemoteLXC test,
which starts a remote node using an LXC container).
The container tests have additional package dependencies (see the toplevel
README). Also, SELinux must be enabled (in either permissive or enforcing mode),
libvirtd must be enabled and running, and root must be able to ssh without a
password between all cluster nodes (not just from the test machine). Before
running the tests, you can verify your environment with:
/usr/share/pacemaker/tests/cts/lxc_autogen.sh -v
LXC tests will create two containers with hardcoded parameters: a NAT'ed bridge
named virbr0 using the IP network 192.168.123.0/24 will be created on the
cluster node hosting the containers; the host will be assigned
52:54:00:A8:12:35 as the MAC address and 192.168.123.1 as the IP address.
Each container will be assigned a random MAC address starting with 52:54:,
the IP address 192.168.123.11 or 192.168.123.12, the hostname lxc1 or lxc2
(which will be added to the host's /etc/hosts file), and 196MB RAM.
The test will revert all of the configuration when it is done.
## Mini-HOWTOs
### Allow passwordless remote SSH connections
The CTS scripts run "ssh -l root" so you don't have to do any of your testing
logged in as root on the test machine. Here is how to allow such connections
without requiring a password to be entered each time:
* On your test exerciser, create an SSH key if you do not already have one.
Most commonly, SSH keys will be in your ~/.ssh directory, with the
private key file not having an extension, and the public key file
named the same with the extension ".pub" (for example, ~/.ssh/id_rsa.pub).
If you don't already have a key, you can create one with:
ssh-keygen -t rsa
* From your test exerciser, authorize your SSH public key for root on all test
machines (both the exerciser and the cluster test machines):
ssh-copy-id -i ~/.ssh/id_rsa.pub root@$MACHINE
You will probably have to provide your password, and possibly say
"yes" to some questions about accepting the identity of the test machines.
The above assumes you have a RSA SSH key in the specified location;
if you have some other type of key (DSA, ECDSA, etc.), use its file name
in the -i option above.
* To test, try this command from the exerciser machine for each
of your cluster machines, and for the exerciser machine itself.
ssh -l root $MACHINE
If this works without prompting for a password, you're in business.
If not, look at the documentation for your version of ssh.

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