Building k8s prometheus adapter

Building k8s-prometheus-adapter

The instructions provided below specify the steps to build k8s-prometheus-adapter version 0.5.0 on Linux on IBM Z for the following distributions:

• RHEL (7.4, 7.5, 7.6)
• SLES (12 SP4, 15)
• Ubuntu (16.04, 18.04, 19.04)

General Notes:

• When following the steps below please use a standard permission user unless otherwise specified

• A directory /<source_root>/ will be referred to in these instructions, this is a temporary writable directory anywhere you'd like to place it

Step 1: Install the Dependencies

 export SOURCE_ROOT=/<source_root>/

• RHEL (7.4, 7.5, 7.6)

  sudo yum install -y tar wget gcc git make curl mercurial       
  

• SLES (12 SP4, 15)

  sudo zypper install -y tar wget gcc git make curl mercurial python-devel
  

• Ubuntu (16.04, 18.04, 19.04)

  sudo apt-get update
  sudo apt-get install -y git make gcc tar curl wget mercurial
  

• Docker packages are provided for SLES, Ubuntu and RHEL (7.5 or higher) in their respective repositories. Instructions for installing Docker on RHEL(7.3) can be found here. You may use the same instructions for RHEL (7.4) as the binaries are expected to be compatible. More information about Docker CE can be found here.

• Install glide

  wget https://github.com/Masterminds/glide/releases/download/v0.13.1/glide-v0.13.1-linux-s390x.tar.gz
  sudo tar -vxz -f glide-v0.13.1-linux-s390x.tar.gz -C /usr/local/bin --strip=1
  export PATH=$PATH:/usr/local/bin
  

• Install Go -- Instructions for building Go can be found here.

Step 2: Build and install k8s-prometheus-adapter

• Setup Environment variable and source folder to build the package

  export GOPATH=$SOURCE_ROOT
  

• Download k8s-prometheus-adapter source code

  mkdir -p $GOPATH/src/github.com/directxman12
  cd $GOPATH/src/github.com/directxman12
  git clone https://github.com/directxman12/k8s-prometheus-adapter.git
  cd k8s-prometheus-adapter
  git checkout v0.5.0
  

• Build k8s-prometheus-adapter

  cd $GOPATH/src/github.com/directxman12/k8s-prometheus-adapter
  make all ARCH=s390x    
  

Step 3: Testing and verifying(Optional)

• Run test cases

  cd $GOPATH/src/github.com/directxman12/k8s-prometheus-adapter
  make test
  make verify
  

Step 4: Deploy k8s-prometheus-adapter to Kubernetes

• Prerequisites

  • A running Kubernetes cluster.

  • Prometheus -- Instructions to install Prometheus server can be found here.

• Create namespace custom-metrics to ensure the namespace we choose to install the custom metrics adapter in.

  kubectl create namespace custom-metrics
  

• Create a secret called cm-adapter-serving-certs with two values: serving.crt and serving.key

  cd $GOPATH/src/github.com/directxman12/k8s-prometheus-adapter
  export PURPOSE=serving
  openssl req -x509 -sha256 -new -nodes -days 365 -newkey rsa:2048 -keyout ${PURPOSE}-ca.key -out ${PURPOSE}-ca.crt -subj "/CN=ca"
  echo '{"signing":{"default":{"expiry":"43800h","usages":["signing","key encipherment","'${PURPOSE}'"]}}}' > "${PURPOSE}-ca-config.json"
  kubectl -n custom-metrics create secret tls cm-adapter-serving-certs --cert=./serving-ca.crt --key=./serving-ca.key
  

• Make changes to $GOPATH/src/github.com/directxman12/k8s-prometheus-adapter/deploy/manifests/custom-metrics-apiserver-deployment.yaml, to point to your prometheus server and k8s-prometheus-adapter docker image.

  @@ -19,13 +19,13 @@ spec:
         serviceAccountName: custom-metrics-apiserver
         containers:
         - name: custom-metrics-apiserver
  -        image: directxman12/k8s-prometheus-adapter-amd64
  +        image: directxman12/k8s-prometheus-adapter:v0.5.0
           args:
           - --secure-port=6443
  -        - --tls-cert-file=/var/run/serving-cert/serving.crt
  -        - --tls-private-key-file=/var/run/serving-cert/serving.key
  +        - --tls-cert-file=/var/run/serving-cert/tls.crt
  +        - --tls-private-key-file=/var/run/serving-cert/tls.key
           - --logtostderr=true
  -        - --prometheus-url=http://prometheus.prom.svc:9090/
  +        - --prometheus-url=http://localhost:9090/
           - --metrics-relist-interval=1m
           - --v=10
           - --config=/etc/adapter/config.yaml

  Notes:
  1. The --tls-private-key-file and --tls-cert-file values are obtained from the values stored in secret cm-adapter-serving-certs. Execute kubectl describe -n custom-metrics secret cm-adapter-serving-certs to view the data.
  2. The --prometheus-url is set to the server and port prometheus server has been started on.

• Deploy k8s-prometheus-adapter

  cd $GOPATH/src/github.com/directxman12/k8s-prometheus-adapter/deploy
  kubectl create -f manifests/
  

  Note: The custom metrics adapter will launch the custom-metrics-apiserver pod.

References:

• https://github.com/DirectXMan12/k8s-prometheus-adapter
• https://github.com/DirectXMan12/k8s-prometheus-adapter/tree/master/deploy
• https://github.com/DirectXMan12/k8s-prometheus-adapter/blob/master/docs/walkthrough.md