Test Suite - KVM

KVM Test framework

Libreswan's test framework can be run using KVM guests, and the kvm scripts. It is strongly recommended to run the test suite on a host machine that has a CPU wth virtualisation instructions.

To access files on the host file system:

• linux guests use the PLAN9 filesystem (9p)
• BSD guests (well openbsd) use NFS via the NAT interface

For an overview of the tests see Test_Suite

Preparing the host machine

Add Yourself to sudo

Some of the test scrips need to be run as root. The test environment assumes this can be done using sudo without a password vis:

sudo pwd

XXX: Surely qemu can be driven without root?

This is done by creating a no-pasword rule to /etc/sudoers.d/.

To set this up, add your account to the wheel group:

sudo usermod -a -G wheel $(id -u -n)

and permit wheel to have no-password access:

echo '%wheel ALL=(ALL) NOPASSWD: ALL' | sudo dd of=/etc/sudoers.d/wheel
sudo chmod ug=r,o= /etc/sudoers.d/wheel
sudo chown root.root /etc/sudoers.d/wheel

Fight SELinux

SELinux blocks some actions that we need. We have not created any SELinux rules to avoid this. The options are:

• set SELinux to permissive (recommended)

sudo sed --in-place=.ORIG -e 's/^SELINUX=.*/SELINUX=permissive/' /etc/selinux/config
sudo setenforce Permissive

• disable SELinux

sudo sed --in-place=.ORIG -e 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config
sudo reboot

• (experimental) label source tree for SELinux

The source tree on the host is shared with the virtual machines. SELinux considers this a bug unless the tree is labelled with type svirt_image_t.

sudo dnf install policycoreutils-python-utils
sudo semanage fcontext -a -t svirt_image_t "$(pwd)"'(/.*)?'
sudo restorecon -vR /home/build/libreswan

There may be other things that SELinux objects to.

Setup Required Dependencies

Now we are ready to install the various components of libvirtd, qemu and kvm and then start the libvirtd service.

Fedora

The following need to be installed:

sudo dnf install -y make git
sudo dnf install -y qemu virt-install libvirt-daemon-kvm libvirt-daemon-qemu
sudo dnf install -y virt-manager           # not necessary but useful
sudo dnf install -y python3-pexpect
sudo dnf install -y dvd+rw-tools           # for building OpenBSDs boot disk
sudo dnf install -y jq nodejs-typescript   # for generating web pages

If you're switching from libvirtd see https://libvirt.org/daemons.html#switching-to-modular-daemons for how to shut down the old daemons.

Start the "collection of modular daemons that replace functionality previously provided by the monolithic libvirtd daemon":

for drv in qemu interface network nodedev nwfilter secret storage
do
   systemctl unmask virt${drv}d.service
   systemctl unmask virt${drv}d{,-ro,-admin}.socket
   systemctl enable virt${drv}d.service
   systemctl enable virt${drv}d{,-ro,-admin}.socket
done
for drv in qemu network nodedev nwfilter secret storage
do
   systemctl start virt${drv}d{,-ro,-admin}.socket
done

There should be no errors and warnings.

If you've plans to run lots of VMs then bump up the constant:

max_workers = 100

in either of (depending on above):

/etc/libvirt/virtqemud.conf

Debian

Anyone?

BSD

Anyone?

Setting Users and Groups

You need to add yourself to the qemu group. For instance:

sudo usermod -a -G qemu $(id -u -n)

You will need to re-login for this to take effect. A cheat is to re-login the current shell:

sudo su - $(id -u -n)

The path to your build needs to be accessible (executable) by root, assuming things are under home:

chmod a+x $HOME

Fix /var/lib/libvirt/qemu

sudo chmod g+w /var/lib/libvirt/qemu

Create /etc/modules-load.d/virtio.conf

Several virtio modules need to be loaded into the host's kernel. This could be done by modprobe ahead of running any virtual machines but it is easier to install them whenever the host boots. This is arranged by listing the modules in a file within /etc/modules-load.d. The host must be rebooted for this to take effect.

sudo dd <<EOF of=/etc/modules-load.d/virtio.conf
virtio_blk
virtio-rng
virtio_console
virtio_net
virtio_scsi
virtio
virtio_balloon
virtio_input
virtio_pci
virtio_ring
9pnet_virtio
EOF

As of Fedora 28, several of these modules are built into the kernel and will not show up in /proc/modules (virtio, virtio_rng, virtio_pci, virtio_ring).

Ensure that the host has enough entropy

Entropy matters

Fedora 32 comes with rng-tools pre-installed.

With KVM, a guest systems uses entropy from the host through the kernel module "virtio_rng" in the guest's kernel (set above). This has advantages:

• entropy only needs to be gathered on one machine (the host) rather than all machines (the host and the guests)
• the host is in the Real World and thus has more sources of real entropy
• any hacking to make entropy available need only be done on one machine

To ensure the host has enough randomness, run either rngd or havegd. The old jitterentropy-rngd code has been merged into rng-tools' rngd.

Fedora commands for using rngd:

sudo dnf install rng-tools
sudo systemctl enable rngd
sudo systemctl start rngd

Fedora commands for using havegd:

sudo dnf install haveged
sudo systemctl enable haveged
sudo systemctl start haveged

Download and configure libreswan

Fetch Libreswan

The libreswan source tree includes all the components that are used on the host and inside the test VMs. To get the latest source code using git:

git clone https://github.com/libreswan/libreswan
cd libreswan

Create the Pool directory for storing VM disk images - $(KVM_POOLDIR)

The pool directory is used used to store VM disk images and other configuration files. By default $(top_srcdir)/../pool is used (that is, adjacent to your source tree).

To change the location of the pool directory, set the KVM_POOLDIR make variable in Makefile.inc.local. For instance:

$ grep KVM_POOLDIR Makefile.inc.local
KVM_POOLDIR=/home/libreswan/pool

(optional) Use /tmp/pool (tmpfs) to store test VM disk images - $(KVM_LOCALDIR)

By default, all disk mages are stored in $(KVM_POOLDIR) (see above). That is both the base VM disk image, and the build VM and test VM disk images. Since only the base VM image needs long-term storage, $(KVM_LOCALDIR) can be used to specify that the build and test images are stored in /tmp:

$ grep KVM_LOCALDIR Makefile.inc.local
KVM_LOCALDIR=/tmp/pool

This has the advantage of eliminating physical disk I/O as a bottle neck when accessing VM disk images; but the disadvantage of needing to re-build the images after a reboot.

(optional) Run tests in parallel - $(KVM_PREFIXES)

By default only one test is run at a time. This can be changed using the $(KVM_PREFIXES) make variable. This provides a list of prefixes to be pretended to test domains creating multiple test groups. The default value is:

KVM_PREFIXES=

which creates the build domains fedora-build, netbsd-build, et.al., and the test domains east, west, et.al. (i.e., after expansion east, west, et.al.).

To run tests in parallel, specify multiple prefixes. For instance two tests can be run in parallel by specifying:

KVM_PREFIXES= 1.

This will create the build domains fedora-build, netbsd-build, et.al., and the test domains east, west, et.al., and separately 1.east, 1.west, et.al.

(optional) Parallel builds - $(KVM_WORKERS)

By default, build domains only have on virtual CPU. Since building is very CPU intensive, this can be increased using $(KVM_WORKERS).

 KVM_WORKERS=2

(optional) Generate a web page of the test results

See the nightly test results for an example.

To create the web directory RESULTS/ and populate it with the current test results use:

make web

The files can the be viewed using http://file.

To disable web page generation, delete the directory RESULTS/.

Alternatively, a web server can be installed and configured:

sudo dnf install httpd
sudo systemctl enable httpd
sudo systemctl start httpd
sudo mkdir /var/www/html/results/
sudo chown $(id -un) /var/www/html/results/
sudo chmod 755 /var/www/html/results/
sudo sh -c 'echo "AddType text/plain .diff" >/etc/httpd/conf.d/diff.conf'

and then $(WEB_SUMMARYDIR) used to specify that the web pages should be published under the server directory:

$ grep WEB_SUMMARYDIR Makefile.inc.local
WEB_SUMMARYDIR=/var/www/html/results

If you want it to be the main page of the website, you can create the file /var/www/html/index.html containing:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
  <head>
    <meta http-equiv="REFRESH" content="0;url=/results/">
  </head>
  <BODY>
  </BODY>
</HTML>

Running the testsuite

In the past, the testsuite was driven using make kvm-... commands. That's largely been replaced by the top-level wrapper script ./kvm which has several advantages over make:

• it is file (file) completion friendly
• it is shell script friendly

For the impatient: ./kvm install check

To build the VMs, and build and install (or update) libreswan, and then run the tests, use:

./kvm install check

Setting up ./kvm (tab completion)

If this:

complete -o filenames -C './kvm' ./kvm

is added to .bashrc then tab completion with ./kvm will include both commands and directories.

Running the testsuite

./kvm install

update the KVMs ready for a new test run

./kvm check

run the testsuite, previous results are saved in BACKUP/-date-

./kvm recheck

run the testsuite, but skip tests that already passed

./kvm results

list the results from the test run

./kvm diffs

display differences between the test results and the expected results, exit non-zero if there are any

the operations can be combined on a single line:

./kvm install check recheck diff

and individual tests can be selected:

./kvm install check diff testing/pluto/*ikev2*

To stop ./kvm use control-c.

Updating Certificates

The full testsuite requires a number of certificates. If not present, then ./kvm check will automatically generate them using the domain build. Just note that the certificates have a limited lifetime. Should the test system detects out-of-date certificates then ./kvm check will barf.

To rebuild the certificates:

./kvm keys

can be used to force the generation of new certificates.

Cleaning up (and general maintenance)

./kvm check-clean

delete the test results

./kvm uninstall

delete the KVM build and test domains (but don't touch the build tree or test results)

./kvm clean

delete the test results, the KVM build and test domains, the build tree, and the certificates

./kvm purge

also delete the test networks (is purge still useful?)

./kvm demolish

also delete the KVM base domain that was used to create the other domains

./kvm upgrade

delete all KVM build and test domains, and then upgrade and transmogrify the base domain ready for a fresh install

./kvm transmogrify

run a fresh transmogrify on the base domain (the base domain is reverted to before the last transmogrify)

./kvm downgrade

revert the base domain back to before it was upgraded (useful when debugging upgrade and transmogrify)

Shell and Console Access (Logging In)

There are several different ways to gain shell access to the domains.

Each method, depending on the situation, has both advantages and disadvantages. For instance:

• while make kvmsh-host provide quick access to the console, it doesn't support file copy
• while SSH takes more to set up, it supports things like proper terminal configuration and file copy

Serial Console access using ./kvm sh HOST (kvmsh.py)

./kvm sh HOST is a wrapper around "virsh" that automatically handles things like booting the machine, logging in, and correctly configuring the terminal. It's big advantage is that it always works. For instance:

$ ./testing/utils/kvmsh.py east
[...]
Escape character is ^]
[root@east ~]# printenv TERM
xterm
[root@east ~]# stty -a
...; rows 52; columns 185; ... 
[root@east ~]#

The script "kvmsh.py" can also be used directly to invoke commands on a guest (this is how ./kvm install works):

$ ./testing/utils/kvmsh.py east ls
[root@east ~]# ls
anaconda-ks.cfg

When $(KVM_PREFIXES) contains multiple prefixes, ./kvm sh east always logs into the first prefixe's domain.

Limitations:

• no file transfer but files can be accessed via /pool and /testing

Graphical Console access using virt-manager

"virt-manager", a gnome tool can be used to access individual domains.

While easy to use, it doesn't support cut/paste or mechanisms for copying files.

Shell access using SSH

While requiring more effort to set up, it provides full shell access to the domains.

Since you will be using ssh a lot to login to these machines, it is recommended to either put their names in /etc/hosts:

# /etc/hosts entries for libreswan test suite
192.1.2.45 west
192.1.2.23 east
192.0.3.254 north
192.1.3.209 road
192.1.2.254 nic

or add entries to .ssh/config such as:

Host west
       Hostname 192.1.2.45

If you wish to be able to ssh into all the VMs created without using a password, add your ssh public key to testing/baseconfigs/all/etc/ssh/authorized_keys. This file is installed as /root/.ssh/authorized_keys on all VMs

Using ssh becomes easier if you are running ssh-agent (you probably are) and your public key is known to the virtual machine. This command, run on the host, installs your public key on the root account of the guest machines west. This assumes that west is up (it might not be, but you can put this off until you actually need ssh, at which time the machine would need to be up anyway). Remember that the root password on each guest machine is "swan".

ssh-copy-id root@west

You can use ssh-copy for any VM. Unfortunately, the key is forgotten when the VM is restarted.

Limitations:

• this only works with the default east, et.al. (it does not work with KVM_PREFIXES and/or multiple test directories)

kvm workflows

(seeing as everyone has a "flow", why not kvm) here are some common workflows, the following commands are used:

./kvm modified

list the test directories that have been modified

./kvm baseline

compare test results against a baseline

./kvm patch

update the expected test results

./kvm add

git add the modified test results

./kvm status

show the status of the currently running testsuite

./kvm kill

kill the currently running testsuite

Working on individual tests

The modified command can be used to limit the test run to just tests with modified files (according to git):

./kvm modified install check diff

install libreswan and then run the testsuite against just the modified tests, display differences differences

./kvm modified recheck diff

re-run the modified tests that are failing, display differences

./kvm modified patch add

update the modified tests applying the latest output and add them to git

this workflow comes into its own, when updating tests en-mass using sed, for instance:

sed -i -e 's/PARENT_//' testing/pluto/*/*.console.txt
./kvm modified check

Checking for regressions

Start by setting up a base directory. Give the KVMs unique bN prefixes (only "b1" is needed, but we're in a hurry so add "b2 b3 b4", 4 boot workers, and /tmp/pool for KVM disk images) and kick off a test run:

$ git clone https://github.com/libreswan/libreswan base
$ cd base
base$ # base - use bN as the prefix
base$ echo KVM_PREFIXES=b1 b2 b3 b4 >> base/Makefile.inc.local
base$ echo KVM_WORKERS=4            >> base/Makefile.inc.local
base$ echo KVM_LOCALDIR=/tmp/pool   >> base/Makefile.inc.local
base$ mkdir -p ../pool
base$ nohup ./kvm install check &
base$ tail -f nohup.out

Next, set up a working directory. This time the KVMs are given the unique wN prefix, and point KVM_BASELINE back at base:

$ git clone https://github.com/libreswan/libreswan work
$ cd work
work$ # work - use wN as the prefix
work$ echo KVM_PREFIXES=w1 w2 w3 w4 >> work/Makefile.inc.local
work$ echo KVM_WORKERS=4            >> work/Makefile.inc.local
work$ echo KVM_BASELINE=../base     >> work/Makefile.inc.local
work$ echo KVM_LOCALDIR=/tmp/pool   >> work/Makefile.inc.local
work$ mkdir -p ../pool

work then then progress in the work directory, and when ready the test run started (here in the background):

work$ ed programs/pluto/plutomain.c
/static bool selftest_only = false/ s/false/true/
w
q
work$ gmake && nohup ./kvm install check &

as the tests progress, the results can be monitored:

work$ ./kvm baseline results
testing/pluto/basic-pluto-01 failed east:baseline-passed,output-different west:baseline-passed,output-different
...
work$ ./kvm baseline diffs testing/pluto/basic-pluto-01
+whack: Pluto is not running (no "/run/pluto/pluto.ctl")

and then the test run aborted, and the problem fixed and tested, and the test run restarted:

work$ ./kvm kill
work$ git checkout -- programs/pluto/plutomain.c
work$ ./kvm install check diff testing/pluto/basic-pluto-01
work$ nohup recheck &

The output can be fine tuned using baseline-failed (show differences when the baseline failed, ignoring passed and unresolved) baseline-passed (show differences when the baseline passed, ignoring failed and unresolved).

To override the KVM_BASELINE make variable, use --baseline DIRECTORY

Tracking down regressions (using git bisect)

Lets assume that the test basic-pluto-01, which was working, is now failing.

The easy way

This workflow works best when the regression is recent (i.e., the last few commits) and nothing significant has happened in the meantime (for instance, os upgrade, test rename, ...).

The command ./kvm install check diff exits with a git bisect friendly status codes which means it can be combined with git bisect run to automate regression testing.

For instance:

git bisect start main ^<suspect-commit>
git bisect run ./kvm install check diff testing/pluto/basic-pluto-01
git bisect visualize
# finally
git bisect reset

The hard way

This workflow works best when trying to track down a regression in an older version of libreswan.

Two repositories are used:

1. repo-under-test

   this contains the sources that will be built and installed into the test domains; it is what git bisect will manipulate

2. testbench

   this contains the test scripts used to test repo-under-test

Start by checking out the two repositories (existing repositories can also be used, carefully):

git clone ... /home/repo-under-test
git clone ... /home/testbench

Next, add the following to /home/testbench/Makefile.inc.local so that the /source directory used by testbench is pointing at repo-under-test:

# repo-under-test's sources are built
KVM_SOURCEDIR=/home/repo-under-test
# testbench's testing directory is used
#KVM_TESTINGDIR=/home/testbench/testing

Next, (re-)transmogrify the testbench so that, within the domains, /source points at repo-under-test:

cd /home/testbench
./kvm transmogrify

Finally run the tests:

cd /home/testbench
git -C /home/repo-under-test bisect start main ^<suspect-commit>
./kvm install check diff testing/pluto/basic-pluto-01
# based on output, pick one:
git bisect {good,bad}
# might work: git -C /home/repo-under-test bisect run -c 'cd ../testbench && ./kvm install check diff testing/pluto/basic-pluto-01
git -C /home/repo-under-test bisect visualize
# finally
git bisect reset

KVM_TESTINGDIR can also be pointed at repo-under-test.

Controlling a test run remotely

Start the testsuite in the background:

nohup ./kvm install check &

To determine if the testsuite is still running:

./kvm status

and to stop the running testsuite:

./kvm kill

Debugging inside the VM (pluto on east)

Terminal 1 - east: log into east, start pluto, and attach gdb

./kvm sh east
east# cd /testing/pluto/basic-pluto-01
east# sh -x ./eastinit.sh
east# gdb /usr/local/libexec/ipsec/pluto $(pidof pluto)
(gdb) c

If pluto isn't running then gdb will complain with: --p requires an argument

Terminal 2 - west: log into west, start pluto and the test

./kvm sh west
west# sh -x ./westinit.sh ; sh -x westrun.sh

When pluto crashes, gdb will show that and await commands. For example, the bt command will show a backtrace.

TODO:

• stop watchdog eventually killing pluto
• notes for west