b131a74f99
Okay, so, at a high level testing NixOS is a lot different than other distros due to NixOS' determinism. Normally NixOS wants packages to be defined in either an overlay, a custom packageOverrides or even yolo-inline as a part of the system configuration. This is going to have us take a different approach compared to other distributions. The overall plan here is as following: 1. make the binaries as normal 2. template in their paths as raw strings to the nixos system module 3. run `nixos-generators -f qcow -o $CACHE_DIR/tailscale/nixos/version -c generated-config.nix` 4. pass that to the steps that make the virtual machine It doesn't really make sense for us to use a premade virtual machine image for this as that will make it harder to deterministically create the image. Nix commands generate a lot of output, so their output is hidden behind the `-verbose-nix-output` flag. This unfortunately makes this test suite have a hard dependency on Nix/NixOS, however the test suite has only ever been run on NixOS (and I am not sure if it runs on other distros at all), so this probably isn't too big of an issue. Signed-off-by: Christine Dodrill <xe@tailscale.com> |
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|---|---|---|
| .. | ||
| doc.go | ||
| nixos_test.go | ||
| opensuse_leap_15_1_test.go | ||
| README.md | ||
| regex_flag_test.go | ||
| regex_flag.go | ||
| runner.nix | ||
| vms_test.go | ||
End-to-End VM-based Integration Testing
This test spins up a bunch of common linux distributions and then tries to get
them to connect to a
testcontrol
server.
Running
This test currently only runs on Linux.
This test depends on the following command line tools:
This test also requires the following:
- about 10 GB of temporary storage
- about 10 GB of cached VM images
- at least 4 GB of ram for virtual machines
- hardware virtualization support (KVM) enabled in the BIOS
- the
kvmmodule to be loaded (modprobe kvm) - the user running these tests must have access to
/dev/kvm(being in thekvmgroup should suffice)
This optionally requires an AWS profile to be configured at the default
path.
The S3 bucket is set so that the requester pays. Please keep this in mind when
running these tests on your machine. If you are uncomfortable with the cost from
downloading from S3, you should pass the -no-s3 flag to disable downloads from
S3. However keep in mind that some distributions do not use stable URLs for each
individual image artifact, so there may be spurious test failures as a result.
If you are using Nix, you can run all of the tests with the correct command line tools using this command:
$ nix-shell -p openssh -p go -p qemu -p cdrkit --run "go test . --run-vm-tests --v --timeout 30m"
Keep the timeout high for the first run, especially if you are not downloading VM images from S3. The mirrors we pull images from have download rate limits and will take a while to download.
Because of the hardware requirements of this test, this test will not run
without the --run-vm-tests flag set.
Other Fun Flags
This test's behavior is customized with command line flags.
Don't Download Images From S3
If you pass the -no-s3 flag to go test, the S3 step will be skipped in favor
of downloading the images directly from upstream sources, which may cause the
test to fail in odd places.
Distribution Picking
This test runs on a large number of distributions. By default it tries to run
everything, which may or may not be ideal for you. If you only want to test a
subset of distributions, you can use the --distro-regex flag to match a subset
of distributions using a regular expression
such as like this:
$ go test -run-vm-tests -distro-regex centos
This would run all tests on all versions of CentOS.
$ go test -run-vm-tests -distro-regex '(debian|ubuntu)'
This would run all tests on all versions of Debian and Ubuntu.
Ram Limiting
This test uses a lot of memory. In order to avoid making machines run out of
memory running this test, a semaphore is used to limit how many megabytes of ram
are being used at once. By default this semaphore is set to 4096 MB of ram
(about 4 gigabytes). You can customize this with the --ram-limit flag:
$ go test --run-vm-tests --ram-limit 2048
$ go test --run-vm-tests --ram-limit 65536
The first example will set the limit to 2048 MB of ram (about 2 gigabytes). The second example will set the limit to 65536 MB of ram (about 65 gigabytes). Please be careful with this flag, improper usage of it is known to cause the Linux out-of-memory killer to engage. Try to keep it within 50-75% of your machine's available ram (there is some overhead involved with the virtualization) to be on the safe side.