auto scale up and down with many named backends in k8s (#270)

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Stein van Broekhoven 2024-02-19 16:54:24 +01:00 committed by GitHub
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docs/k8s-autoscale.yaml Normal file
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# This YAML is an example and is not intended to be directly applied.
# It consists of 3 parts
# 1. the mc-router with service account an service
# 2. the shutdown cronjob with service account
# 3. the actual server with service and storage
# part 3 is the only part you need to replicate for the number of servers you want
# mc-router
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: mc-router
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: services-watcher
rules:
- apiGroups: [""]
resources: ["services"]
verbs: ["watch","list"]
- apiGroups: ["apps"]
resources: ["statefulsets", "statefulsets/scale"]
verbs: ["watch","list","get","update"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: mc-router-services-watcher
subjects:
- kind: ServiceAccount
name: mc-router
namespace: default
roleRef:
kind: ClusterRole
name: services-watcher
apiGroup: rbac.authorization.k8s.io
# Use whatever tcp ingress method you want I just used a node port here for simplicity
---
apiVersion: v1
kind: Service
metadata:
name: mc-router
spec:
type: NodePort
externalIPs:
- 192.168.1.100
ports:
- targetPort: web
name: web
port: 8080
nodePort: 30001
- targetPort: proxy
name: proxy
port: 25565
nodePort: 30000
selector:
run: mc-router
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
run: mc-router
name: mc-router
spec:
selector:
matchLabels:
run: mc-router
strategy:
type: Recreate
template:
metadata:
labels:
run: mc-router
spec:
serviceAccountName: mc-router
containers:
- image: aapjeisbaas/mc-router:latest
imagePullPolicy: Always
name: mc-router
args: ["--api-binding", ":8080", "--in-kube-cluster","--auto-scale-up", "--debug"]
env:
- name: AUTO_SCALE_UP
value: "true"
ports:
- name: proxy
containerPort: 25565
- name: web
containerPort: 8080
resources:
requests:
memory: 50Mi
cpu: "100m"
limits:
memory: 100Mi
cpu: "250m"
# Cron job for stopping empty servers
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
name: mc-shutdown
rules:
- apiGroups: ["apps"]
resources: ["statefulsets", "statefulsets/scale"]
verbs: ["list","get","update", "patch"]
- apiGroups: [""]
resources: ["pods", "pods/log"]
verbs: ["get", "list"]
- apiGroups: [""]
resources: ["pods/exec"]
verbs: ["create"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: mc-shutdown
subjects:
- kind: ServiceAccount
name: mc-shutdown
namespace: default
roleRef:
kind: ClusterRole
name: mc-shutdown
apiGroup: "rbac.authorization.k8s.io"
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: mc-shutdown
---
apiVersion: batch/v1
kind: CronJob
metadata:
name: mc-shutdown
spec:
schedule: "*/5 * * * *"
concurrencyPolicy: Forbid
jobTemplate:
spec:
template:
spec:
serviceAccountName: mc-shutdown
restartPolicy: OnFailure
containers:
- name: shutdown
image: bitnami/kubectl:latest
imagePullPolicy: IfNotPresent
command:
- /bin/bash
- -c
- source shutdown-script.sh
volumeMounts:
- name: shutdown-script
mountPath: /shutdown-script.sh
subPath: shutdown-script.sh
readOnly: true
volumes:
- name: shutdown-script
configMap:
name: shutdown-script
items:
- key: shutdown-script.sh
path: shutdown-script.sh
# uses container label containertype=minecraft-server to find running servers
# TODO: get ownerReferences link to StatefulSet/name from pod metadate instead of sed string manipulation
---
apiVersion: v1
kind: ConfigMap
metadata:
name: shutdown-script
data:
shutdown-script.sh: |
#!/bin/bash
MC_PODS=$(kubectl get pods -l containertype=minecraft-server -o=jsonpath="{range .items[*]}{.metadata.name},"| sed 's/,/\n/g')
for p in $MC_PODS; do
echo "found minecraft pod $p, sleeping 120 seconds to prevent shutdown before login"
sleep 120
deployment=$(echo $p |sed 's/-0//g')
# check online player count in the mc server
if [[ $(kubectl exec -i $p -- /usr/local/bin/mc-monitor status) == *"online=0"* ]] ;then
kubectl scale statefulset $deployment --replicas=0
fi
done
# The actual minecraft servers, services and storage, repeat this block for as many servers as you want
# make sure you have the label containertype=minecraft-server this is used to find running servers
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: minecraft-servername-deployment
labels:
app: minecraft-servername-container
spec:
serviceName: minecraft-servername-deployment
selector:
matchLabels:
app: minecraft-servername-container
replicas: 0
template:
metadata:
labels:
app: minecraft-servername-container
containertype: minecraft-server
spec:
containers:
- name: minecraft-servername-deployment
image: itzg/minecraft-server:latest
imagePullPolicy: IfNotPresent
resources:
limits:
memory: "2048Mi"
env:
# Use secret in real usage
- name: EULA
value: "true"
# let the JVM figure out mem management
- name: "MEMORY"
value: ""
- name: JVM_XX_OPTS
value: "-XX:MaxRAMPercentage=75"
ports:
- containerPort: 25565
name: main
readinessProbe:
exec:
command: [ "/usr/local/bin/mc-monitor", "status", "--host", "localhost" ]
# Give it i + p * f seconds to be ready, so 120 seconds
initialDelaySeconds: 20
periodSeconds: 5
failureThreshold: 20
# Monitor ongoing liveness
livenessProbe:
exec:
command: ["/usr/local/bin/mc-monitor", "status", "--host", "localhost"]
initialDelaySeconds: 120
periodSeconds: 60
volumeMounts:
- name: mc-data
mountPath: /data
volumes:
- name: mc-data
persistentVolumeClaim:
claimName: minecraft-servername-pvc
readOnly: false
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: minecraft-servername-pvc
namespace: default
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 20Gi
---
apiVersion: v1
kind: Service
metadata:
name: minecraft-servername-deployment
namespace: default
annotations:
"mc-router.itzg.me/externalServerName": "your-awesome-server.public-domain.com"
spec:
ports:
- port: 25565
selector:
app: minecraft-servername-container