ci: prepare ISO artifacts in parallel with kola run

[bgilbert]

No description provided.

[jlebon]

Hmm, maybe with something like:

diff --git a/.cci.jenkinsfile b/.cci.jenkinsfile
index 2885b61..21e753a 100644
--- a/.cci.jenkinsfile
+++ b/.cci.jenkinsfile
@@ -1,6 +1,6 @@
 // Documentation: https://github.com/coreos/coreos-ci/blob/master/README-upstream-ci.md

-cosaPod(buildroot: true) {
+cosaPod(buildroot: true, ram: "11Gi") {
     checkout scm

     // hack to satisfy golang compiler wanting to cache things

? That'd be 1G per VM (8 for kola + 1 for blackbox + 1 for testiso) + another for overhead.

[jlebon]

Actually testiso takes 4G because of coreos/fedora-coreos-tracker#407, so we'd have to make it 15Gi, which is starting to get big. One thing we could do is parallelize the cosa buildextends at least so it runs while the kola tests run, but still leave the testiso itself after the others.

[bgilbert]

Turns out this makes the whole run slower. It extends the first parallel phase by ~4.5 minutes, and in the second parallel phase, buildextend + compress + testiso is faster than the blackbox tests anyway.