Kondense is an automated memory sizing tool. It runs as a sidecar in kubernetes pods.

Kondense uses real-time memory pressure to determine the optimal memory for each containers in a pod.

Allocated memory is not a good proxy for required memory. Many libraries used during startup are loaded into memory only to be never touched again afterwards.

Kondense uses the memory pressure given by the Linux Kernel to apply just the right amount of memory on a container to page out the unused memory while not getting out-of-memory killed.

1. The Kubernetes cluster must run on Linux.
2. Kubernetes version >= 1.27.
3. Containerd version >= 1.6.9.
4. Kubernetes should have the feature gate InPlacePodVerticalScaling enabled.

1. Containers should have the binary cat.
2. Containers should include the linux kernel version >= 4.20. Ensure the file /sys/fs/cgroup/memory.pressure exists in the container to verify it.

Try the example on minikube:

minikube start --kubernetes-version=v1.29.2 --feature-gates=InPlacePodVerticalScaling=true
kubectl apply -f https://raw.githubusercontent.com/unagex/kondense/main/example/nginx.yaml

Let's say we have a pod running nginx that we want to Kondense:

apiVersion: v1
kind: Pod
metadata:
  name: kondense-test
spec:
  serviceAccountName: nginx-user
  containers:
  - name: nginx
    image: nginx:latest
    resources:
      limits:
        cpu: 0.1
        memory: 100M

Add Kondense as a sidecar:

apiVersion: v1
kind: Pod
metadata:
  name: kondense-test
spec:
  serviceAccountName: nginx-user
  containers:
  - name: nginx
    image: nginx:latest
    resources:
      limits:
        cpu: 0.1
        memory: 100M
  - name: kondense
    image: kondense/kondense:1.0.1
    resources:
      limits:
        cpu: 0.3
        memory: 50M

Notes:

1. The pod should have a QoS of Guaranteed. In other words, we need to add resources limits for each containers.
2. The service account nginx-user should have the following rules:

rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["get", "list", "watch", "patch"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create"]

After adding the kondense container, the nginx container memory will be updated dynamically without any container restart.

Kondense is configurable via environment variables in the kondense container.

    ...
    - name: kondense
      image: kondense/kondense:1.0.1
      resources:
        limits:
          cpu: 0.3
          memory: 50M
      env:
      - name: <CONTAINER NAME>_MEMORY_INTERVAL
        value: "5"

If we have a container named nginx in our pod, the variable name should be NGINX_MEMORY_INTERVAL.

• Kondense is based on Facebook senpai
• Kondense is active on himself by default