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https://github.com/mbogus/docker-kube-amqp-autoscale

Dynamically scale kubernetes resources using length of an AMQP queue
https://github.com/mbogus/docker-kube-amqp-autoscale

auto-scaling autoscale autoscaler autoscaling docker-image kubernetes

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Dynamically scale kubernetes resources using length of an AMQP queue

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# KUBE-AMQP-AUTOSCALE Dockerfile



Dynamically scale kubernetes resources using length of an AMQP queue (number of messages available for retrieval from the queue) to determine the load on an application/Kubernetes pod.



**NOTICE**

If your application load is not queue-bound but rather CPU-sensitive, make sure to use built-in Kubernetes [Horizontal Pod Autoscaling](http://kubernetes.io/docs/user-guide/horizontal-pod-autoscaling/) instead of this project.



This repository contains **Dockerfile** of [KUBE-AMQP-AUTOSCALE](http://www.github.com/mbogus/kube-amqp-autoscale/) for [Docker](https://www.docker.com/)'s [automated build](https://hub.docker.com/r/mbogus/kube-amqp-autoscale/) published to the public [Docker Hub Registry](https://registry.hub.docker.com/).



## Base Docker Image



* [ubuntu](https://hub.docker.com/_/ubuntu/)



## Installation



1. Install [Docker](https://www.docker.com/).



2. Download [automated build](https://hub.docker.com/r/mbogus/kube-amqp-autoscale/) from public [Docker Hub Registry](https://registry.hub.docker.com/): `docker pull mbogus/kube-amqp-autoscale`



   (alternatively, you can build an image from Dockerfile: `docker build -t="mbogus/kube-amqp-autoscale" github.com/mbogus/docker-kube-amqp-autoscale`)



## Usage



### Run `autoscale`



    docker run -d -e AUTOSCALE_NAME=pod_to_scale -e AUTOSCALE_THRESHOLD=50 -e AUTOSCALE_MAX=10 -e RABBITMQ_URI=amqp://guest:[email protected]:5672// -e RABBITMQ_QUEUE=queue_to_watch -e KUBERNETES_SERVICE_URL=http://127.0.0.1:8080 mbogus/kube-amqp-autoscale



### Run `autoscale` w/ persistent shared directories.



    docker run -d -v :/data/db -v :/etc/default -e AUTOSCALE_NAME=pod_to_scale -e AUTOSCALE_THRESHOLD=50 -e AUTOSCALE_MAX=10 -e RABBITMQ_URI=amqp://guest:[email protected]:5672// -e RABBITMQ_QUEUE=queue_to_watch -e KUBERNETES_SERVICE_URL=http://127.0.0.1:8080 mbogus/kube-amqp-autoscale



### Configuration environment variables:



#### Autoscale service:



* `AUTOSCALE_NS` Kubernetes namespace (default `default`)

* `AUTOSCALE_KIND` type of the Kubernetes resource to autoscale, one of `Deployment`, `ReplicationController`, `ReplicaSet` (default `Deployment`)

* `AUTOSCALE_NAME` name of the Kubernetes resource to autoscale

* `AUTOSCALE_THRESHOLD` number of messages on a queue representing maximum load on the autoscaled Kubernetes resource

* `AUTOSCALE_MIN` lower limit for the number of replicas for a Kubernetes pod that can be set by the autoscaler (default `1`)

* `AUTOSCALE_MAX` upper limit for the number of replicate for a Kubernetes pod that can be set by the autoscaler

* `AUTOSCALE_INTERVAL` time interval between Kubernetes resource scale runs in secs (default `30`)

* `AUTOSCALE_INCREASE_LIMIT` limit number of Kubernetes pods to be provisioned in a single scale iteration to max of the value, set to a number greater than 0, default `unbounded`

* `AUTOSCALE_DECREASE_LIMIT` limit number of Kubernetes pods to be terminated in a single scale iteration to max of the value, set to a number greater than 0, default `unbounded`



#### Autoscale statistics



* `AUTOSCALE_STATS_COVERAGE` required percentage of statistics to calculate average queue length (default `0.75`)

* `AUTOSCALE_STATS_INTERVAL` time interval between metrics gathering runs in seconds (default `5`)

* `AUTOSCALE_EVAL_INTERVALS` number of autoscale intervals used to calculate average queue length (default `2`)

* `AUTOSCALE_DB` sqlite3 database filename for storing  queue length statistics (default `:memory:`)



#### RabbitMQ broker and queue definitions



*Recommendations:*



* if RabbitMQ is deployed externally (not part of the Kubernetes cluster), use complete URI to locate the broker: `RABBITMQ_URI`

* if RabbitMQ is part of the cluster and DNS service has been configured, use DNS name: `RABBITMQ_HOST`

* if RabbitMQ is part of the cluster but DNS service has not been configured, try using Kubernetes service name for the broker: `KUBERNETES_RABBITMQ_SERVICE_NAME`

* whenever you can, stick to defaults



*Variables:*



* `RABBITMQ_URI` required, RabbitMQ broker URI, e.g. `amqp://guest:[email protected]:5672//`

or:

* `RABBITMQ_HOST` RabbitMQ broker hostname (default `127.0.0.1`)

* `RABBITMQ_PORT` port number (default `5672`)

* `KUBERNETES_RABBITMQ_SERVICE_NAME` name of Kubernetes service exposing RabbitMQ broker

* `RABBITMQ_PROTO` use `amqps` for secure connections (default `amqp`)

* `RABBITMQ_USER` user name (default `guest`)

* `RABBITMQ_PASS` password (default `guest`)

* `RABBITMQ_VHOST` virtual host (default `/`)



* `RABBITMQ_QUEUE` RabbitMQ queue name to measure load on an application



#### Kubernetes cluster access



* `KUBERNETES_SERVICE_URL` Kubernetes API URL, e.g. `http://127.0.0.1:8080`

or

* `KUBERNETES_SERVICE_PROTO` (default `https`)

* `KUBERNETES_SERVICE_HOST` (default `127.0.0.1`)

* `KUBERNETES_SERVICE_PORT` (default `443`)



* `KUBERNETES_SERVICE_INSECURE` Set to `true` for connecting to Kubernetes API

  without verifying TLS certificate; unsafe, use for development only (default `false`)



**Basic authentication**



* `KUBERNETES_SERVICE_USERNAME` username for basic authentication on Kubernetes API

* `KUBERNETES_SERVICE_PASSWORD` password for basic authentication on Kubernetes API



**OAuth2 authentication (inside Kubernetes pod)**



Path to a bearer token file for OAuth authentication, on a Kubernetes pod

`/var/run/secrets/kubernetes.io/serviceaccount/token`



**TSL certificate (inside Kubernetes pod)**



Path to CA certificate file for HTTPS connections to Kubernetes API from

within a cluster `/var/run/secrets/kubernetes.io/serviceaccount/ca.crt`



## Sample Kubernetes deployment file



An all-in-one deployment that comprises of a RabbitMQ broker (`rabbitmq-broker`),

a worker node (`echo-node`) to be scaled according to number of unacknowledged

messages on `EchoQueue` queue and the autoscaler deployed as `autoscaler` adding

one node for each waiting message on the queue capped at 5.



~~~

---

apiVersion: v1

kind: Service

metadata:

  labels:

    app: autoscale-example

    component: broker

  name: rabbitmq-broker

spec:

  ports:

  - port: 5672

    name: main-port

    nodePort: 30672

  - port: 15672

    name: admin-port

    nodePort: 30080

  type: NodePort

  selector:

    app: autoscale-example

    component: broker

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: rabbitmq-broker

spec:

  replicas: 1

  template:

    metadata:

      labels:

        app: autoscale-example

        component: broker

    spec:

      containers:

      - name: rabbitmq

        image: rabbitmq:3-management

        imagePullPolicy: Always

        env:

        - name: RABBITMQ_HIPE_COMPILE

          value: "1"

        resources:

          requests:

            cpu: 200m

            memory: 200Mi

          limits:

            cpu: 500m

            memory: 500Mi

        ports:

        - containerPort: 5672

          hostPort: 5672

        - containerPort: 15672

          hostPort: 15672

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: echo-node

spec:

  replicas: 1

  template:

    metadata:

      labels:

        app: autoscale-example

        component: worker

    spec:

      containers:

      - name: echo

        image: mbogus/amqp-echo

        imagePullPolicy: Always

        env:

        - name: KUBERNETES_RABBITMQ_SERVICE_NAME

          value: RABBITMQ_BROKER

        - name: RABBITMQ_QUEUE

          value: EchoQueue

        - name: ECHO_DELAY

          value: "15"

        resources:

          requests:

            cpu: 100m

            memory: 100Mi

          limits:

            cpu: 200m

            memory: 200Mi

---

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: autoscaler

spec:

  replicas: 1

  template:

    metadata:

      labels:

        app: autoscale-example

        component: scaler

    spec:

      containers:

      - name: autoscale

        image: mbogus/kube-amqp-autoscale

        imagePullPolicy: Always

        env:

        - name: AUTOSCALE_NAME

          value: echo-node

        - name: AUTOSCALE_THRESHOLD

          value: "1"

        - name: AUTOSCALE_MAX

          value: "5"

        - name: RABBITMQ_QUEUE

          value: EchoQueue

        - name: KUBERNETES_RABBITMQ_SERVICE_NAME

          value: RABBITMQ_BROKER

        resources:

          requests:

            cpu: 100m

            memory: 100Mi

          limits:

            cpu: 200m

            memory: 200Mi

~~~