35coreos-ignition: add coreos-kargs

[arithx]

Marking as draft until an Ignition release & coreos-installer release have made it to testing-devel.

Based on content from these PRs:
coreos/ignition#1178
coreos/coreos-installer#498

[jlebon]

Some bikesheddy nits, but LGTM overall!

[arithx]

Rebased on top of #1009

[jlebon]

Awesome! 🎉

[jlebon]

Were you thinking of enhancing kola to allow setting kargs from external tests? Or just have internal tests in kola for now?

[arithx]

Were you thinking of enhancing kola to allow setting kargs from external tests? Or just have internal tests in kola for now?

Are you meaning kargs set via the harness (e.x. set via the qemu cmdline args) specifically for testing this feature? If so my plan was to just have it be an internal test, any other test that wants kargs can just add it to the Ignition config (as that's the user-facing happy path we are trying to enable here).

[jlebon]

Are you meaning kargs set via the harness (e.x. set via the qemu cmdline args) specifically for testing this feature? If so my plan was to just have it be an internal test, any other test that wants kargs can just add it to the Ignition config (as that's the user-facing happy path we are trying to enable here).

Heh right sorry, I got mixed up. Obviously, since this is in the Ignition config now (that was the whole point!) it shouldn't need any more work in the kola harness for external tests. So adding a test for this here should be pretty trivial. Something like:

diff --git a/tests/kola/ignition/kargs/config.ign b/tests/kola/ignition/kargs/config.ign
new file mode 100644
index 0000000..3d6d859
--- /dev/null
+++ b/tests/kola/ignition/kargs/config.ign
@@ -0,0 +1,9 @@
+{
+  "ignition": {
+    "version": "3.3.0-experimental"
+  },
+  "kernelArguments": {
+    "shouldExist": "foobar",
+    "shouldNotExist": "mitigations=auto,nosmt"
+  }
+}
diff --git a/tests/kola/ignition/kargs/test.sh b/tests/kola/ignition/kargs/test.sh
new file mode 100755
index 0000000..a753525
--- /dev/null
+++ b/tests/kola/ignition/kargs/test.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+set -xeuo pipefail
+
+ok() {
+    echo "ok" "$@"
+}
+
+fatal() {
+    echo "$@" >&2
+    exit 1
+}
+
+if ! grep foobar /proc/cmdline; then
+    fatal "missing foobar in kernel cmdline"
+fi
+if grep mitigations /proc/cmdline; then
+    fatal "found mitigations in kernel cmdline"
+fi
+ok "Ignition kargs"

WDYT?

Cool with an internal test if you prefer, though we're trying to move towards external tests when possible. A nice advantage for example is that we can then test the code added here in CI before merging. But again, feel free to self-merge if you want to do this in kola proper or as a follow-up.

[arithx]

Cool with an internal test if you prefer, though we're trying to move towards external tests when possible. A nice advantage for example is that we can then test the code added here in CI before merging. But again, feel free to self-merge if you want to do this in kola proper or as a follow-up.

My thought on an internal test was so that we could also test the shouldNotExist by adding a karg from the harness side and removing it w/ Ignition but the nosmt one would work.

[arithx]

Went ahead and pushed with your patch (and added you as a co-author of the commit).

[jlebon]

[2021-05-14T19:33:52.998Z] 2021-05-14T19:33:52Z platform/conf: invalid userdata: error at line 6 col 28: json: cannot unmarshal string into Go struct field KernelArguments.kernelArguments.shouldExist of type []types.KernelArgument
[2021-05-14T19:33:52.998Z] Error: Parsing config.ign: config is not valid
[2021-05-14T19:33:52.998Z] 2021-05-14T19:33:52Z cli: Parsing config.ign: config is not valid

Ahh right OK, this does still require teaching the new spec to kola like we did here. I think we'll need that anyway eventually, though OK to not block on that.

[arithx]

[2021-05-14T19:33:52.998Z] 2021-05-14T19:33:52Z platform/conf: invalid userdata: error at line 6 col 28: json: cannot unmarshal string into Go struct field KernelArguments.kernelArguments.shouldExist of type []types.KernelArgument
[2021-05-14T19:33:52.998Z] Error: Parsing config.ign: config is not valid
[2021-05-14T19:33:52.998Z] 2021-05-14T19:33:52Z cli: Parsing config.ign: config is not valid

Ahh right OK, this does still require teaching the new spec to kola like we did here. I think we'll need that anyway eventually, though OK to not block on that.

That was actually an error in the tests Ignition config (it was passing a string to shouldExist/shouldNotExist instead of a list of strings).

Ignition 2.10.1 was vendored into mantle in coreos/coreos-assembler#2165

[jlebon]

[2021-05-14T20:38:04.936Z] --- PASS: ext.config.ignition.kargs (37.22s)

Awesome! 🎉

[lucab]

I'm not exactly sure what's going on, but I'm now seeing the following in FCOS build logs:

dracut: *** Including module: coreos-ignition ***
mv: cannot remove '/usr/lib/dracut/modules.d/35coreos-ignition/coreos-kargs.sh': Read-only file system

[jlebon]

Thanks, follow-up in #1076.