🔧 Disable threading in flask debug server

For educational purposes, the RNG service is meant to process only one request at a time (without concurrency). But the flask server now defaults to a multi-threaded implementation, which defeats our original purpose. So here we disable threading to restore the original behavior.
🔧 updates documentation links that changed
2026-02-15 01:59:57 +00:00 · 2026-01-30 13:00:01 +01:00 · 2026-01-28 15:31:00 +01:00 · 2026-01-27 08:50:23 +01:00 · 2026-01-27 08:49:04 +01:00
5 changed files with 10 additions and 7 deletions
--- a/dockercoins/rng/Dockerfile
+++ b/dockercoins/rng/Dockerfile
@@ -3,5 +3,5 @@ WORKDIR /app
 RUN pip install Flask
 COPY rng.py .
 ENV FLASK_APP=rng FLASK_RUN_HOST=:: FLASK_RUN_PORT=80
-CMD ["flask", "run"]
+CMD ["flask", "run", "--without-threads"]
 EXPOSE 80
--- a/k8s/haproxy.cfg
+++ b/k8s/haproxy.cfg
@@ -12,5 +12,5 @@ listen very-basic-load-balancer
  server blue color.blue.svc:80
  server green color.green.svc:80

-# Note: the services above must exist,
-# otherwise HAproxy won't start.
+### Note: the services above must exist,
+### otherwise HAproxy won't start.
--- a/prepare-labs/konk.sh
+++ b/prepare-labs/konk.sh
@@ -5,6 +5,9 @@
 # 10% CPU
 # (See https://docs.google.com/document/d/1n0lwp6rQKQUIuo_A5LQ1dgCzrmjkDjmDtNj1Jn92UrI)
 # PRO2-XS = 4 core, 16 gb
+# Note that we also need 2 volumes per vcluster (one for vcluster itself, one for shpod),
+# so we might hit the maximum number of volumes per node!
+# (TODO: check what that limit is on Scaleway and Linode)
 #
 # With vspod:
 # 800 MB RAM
@@ -15,7 +18,7 @@ set -e

 KONKTAG=konk
 PROVIDER=linode
-STUDENTS=5
+STUDENTS=2

 case "$PROVIDER" in
 linode)
--- a/prepare-labs/terraform/one-kubernetes/vcluster/main.tf
+++ b/prepare-labs/terraform/one-kubernetes/vcluster/main.tf
@@ -4,7 +4,7 @@ resource "helm_release" "_" {
  create_namespace = true
  repository       = "https://charts.loft.sh"
  chart            = "vcluster"
-  version          = "0.27.1"
+  version          = "0.30.4"
  values = [
    yamlencode({
      controlPlane = {
--- a/slides/k8s/daemonset.md
+++ b/slides/k8s/daemonset.md
@@ -729,8 +729,8 @@ class: extra-details

 - Relevant documentation:

-  [Service spec](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.19/#servicespec-v1-core),
-  [LabelSelector spec](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.19/#labelselector-v1-meta),
+  [Service spec](https://kubernetes.io/docs/reference/kubernetes-api/service-resources/service-v1/#ServiceSpec),
+  [LabelSelector spec](https://kubernetes.io/docs/reference/kubernetes-api/common-definitions/label-selector/),
  [label selector doc](https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors)

 ---
Author	SHA1	Message	Date
Jérôme Petazzoni	8ba96380b7	🔧 Disable threading in flask debug server For educational purposes, the RNG service is meant to process only one request at a time (without concurrency). But the flask server now defaults to a multi-threaded implementation, which defeats our original purpose. So here we disable threading to restore the original behavior.	2026-01-30 13:00:01 +01:00
Olivier Delhomme	4311a09ccd	🔧 updates documentation links that changed	2026-01-28 15:31:00 +01:00
Jérôme Petazzoni	feb0a8cdb9	Use multiple # in included files' comments ...otherwise that causes side effects with the TOC generator 🙈	2026-01-27 08:50:23 +01:00
Jérôme Petazzoni	302924db40	🔧 Bump up vcluster version to work around weird bug (Probably due to K8S version mismatch; vcluster was on 1.33 and the host cluster was on 1.35. Symptoms: some pods start, all their containers are ready, the pod shows up as ready, and yet, it's not considered ready so the deployment says 0/1 and Helm never completes.)	2026-01-27 08:49:04 +01:00