Disable http/grpc mux for etcd

[brandond]

Tracking issue for:

• Etcd watch stream starvation under high read response load when sharing same connection and TLS is enabled etcd-io/etcd#15402

The etcd project has documented issues with watch stream starvation under load when http and grpc are muxed on the same TLS listener.

• For embedded etcd, we need to enable http on a different port, enable to free the main client port for dedicated grpc use
• For kine, we should investigate whether or not this same issue affects unencrypted unix sockets, or if it only applies to TCP/TLS listeners.

[mdrahman-suse]

Validated on master branch with commit 00fc5a2

Environment Details

Infrastructure

• Cloud
• Hosted

Node(s) CPU architecture, OS, and Version:

Ubuntu 22.04.2 LTS (GNU/Linux 5.15.0-1031-aws x86_64)

Cluster Configuration:

1 server

Config.yaml:

write-kubeconfig-mode: 644
cluster-init: true
node-external-ip: <public-ip>

Testing Steps

1. Copy config.yaml

$ sudo mkdir -p /etc/rancher/k3s && sudo cp config.yaml /etc/rancher/k3s

2. Install k3s
3. Wait for the cluster to be up and running
4. Check the logs using: $ sudo journalctl -u k3s | grep "Running http"
5. Ensure no error message is displayed

Replication Results:

• k3s version used for replication:

$ k3s -v
k3s version v1.28.2+k3s1 (6330a5b4)
go version go1.20.8

• Observed warn message in logs

$ sudo journalctl -u k3s | grep "Running http"
Oct 05 15:43:03 ip-xxx-xx-xx-174 k3s[1670]: {"level":"warn","ts":"2023-10-05T15:43:03.366688Z","caller":"embed/config.go:673","msg":"Running http and grpc server on single port. This is not recommended for production."}
Oct 05 15:43:03 ip-xxx-xx-xx-174 k3s[1670]: {"level":"warn","ts":"2023-10-05T15:43:03.366755Z","caller":"embed/config.go:673","msg":"Running http and grpc server on single port. This is not recommended for production."}

Validation Results:

• k3s version used for validation:

$ k3s -v
k3s version v1.28.2+k3s-00fc5a23 (00fc5a23)
go version go1.20.8

• Observed NO warn message in logs

$ sudo journalctl -u k3s | grep "Running http"
ubuntu@ip-xxx-xxx-xx-174:~$

[jaysonsantos]

Hi there, for those who rely on this feature 🙈 on constrained systems, is there a way to enable it once more? After updating to 1.27.7 a small service stopped working because it uses lua with the http version.