Support multiple kCTF clusters in the same project

[sroettger]

This is desired if you want to provide challenges in different regions.

Some things that are broken currently:

• subnet is hardcoded in the startup script
• DNS entries get overwritten when deploying challenges with the same name
• With multiple clusters I am not sure if I should be using a single kctf-conf/ directory with different cluster configs in there, or if it's ok to have multiple kctf-conf directories
• Given that the cluster configs are setup using symlinks I cannot run commands in multiple clusters in different shells. Maybe we should allow changing the cluster config based on an environment variable.
• namespace challenge docker images to the cluster they belong to #199 two tasks with the same name override each other

[sirdarckcat]

does this cover #133?

[sroettger]

I think that's the first bullet point?

[sirdarckcat]

I closed the other one then, feel free to reopen if you want to track each bullet independently.

[sirdarckcat]

I think then this is also #16 - closing that one too

[sirdarckcat]

Re:

[ ] subnet is hardcoded in the startup script

That means changing 172.16.0.32/28 to something else somehow in the line below

kctf/dist/bin/kctf-cluster

Line 26 in 0ef4b04

gcloud container clusters create --release-channel=regular --enable-network-policy --enable-autoscaling --min-nodes ${MIN_NODES} --max-nodes ${MAX_NODES} --num-nodes ${NUM_NODES} --create-subnetwork name=kctf-${CLUSTER_NAME}-subnet --no-enable-master-authorized-networks --enable-ip-alias --enable-private-nodes --master-ipv4-cidr 172.16.0.32/28 --enable-autorepair --preemptible --machine-type ${MACHINE_TYPE} --workload-pool=${PROJECT}.svc.id.goog ${CLUSTER_NAME}

[sirdarckcat]

Re:

[ ] DNS entries get overwritten when deploying challenges with the same name

I think domain names are namespaced in the global (DNS) namespace, not the project one, so we can't really fix that =/