Google Kubernetes Engine and WEKA over POSIX deployment

curl -sS -H 'Metadata-Flavor: Google' 'http://metadata.google.internal/computeMetadata/v1/instance/?recursive=true&alt=json' | jq '.attributes."cluster-name"' -r

(
    #!/usr/bin/env bash

    set -euo pipefail

    DEBIAN_FRONTEND=noninteractive
    ROOT_MOUNT_DIR="${ROOT_MOUNT_DIR:-/root}"
    
    export WEKA_FS="default"

    # Mount point for weka filesystem
    export WEKA_MOUNT="/mnt/gkeclient"
    
    # Its good to add 2-3 servers in case one is not available 
    export WEKA_HOSTS="10.0.0.8,10.0.0.9,10.0.0.10"
    
    # Timeout for how long the client is inaccessible before being removed from the cluster
    
    # Default is 86400 (24hrs) in a more dynamic environment it can be lower. 
    export WEKA_CLIENTTIMEOUNT="3600"
    
    # Number of cores to add to WEKA FrontEnd.
    export WEKA_FRONTENDCORES=2
    
    # First IP taken from WEKA_HOSTS list to download the client from.
    export WEKA_DOWNLOADIP=$(echo "$WEKA_HOSTS" | cut -d',' -f1)
  
  
    echo "Installing dependencies"
    apt-get update
    apt-get install -y apt-transport-https curl gnupg lsb-release jq

    echo "Installing gcloud SDK"
    snap install google-cloud-sdk --classic

    echo "Getting node metadata"
    ALL_METADATA="$(curl -sS -H 'Metadata-Flavor: Google' 'http://metadata.google.internal/computeMetadata/v1/instance/?recursive=true&alt=json')"
    NODE_NAME="$(curl -sS http://metadata.google.internal/computeMetadata/v1/instance/name -H 'Metadata-Flavor: Google')"
    ZONE="$(curl -sS http://metadata.google.internal/computeMetadata/v1/instance/zone -H 'Metadata-Flavor: Google' | awk -F  "/" '{print $4}')"

    echo "Setting up disks"
    DISK_NAME="$NODE_NAME-wekadir"

    if ! gcloud compute disks list --filter="name:$DISK_NAME" | grep "$DISK_NAME" > /dev/null; then
        echo "Creating $DISK_NAME"
        gcloud compute disks create "$DISK_NAME" --size=$(( 1024*20 )) --zone="$ZONE"
    else
        echo "$DISK_NAME already exists"
    fi

    if ! gcloud compute instances describe "$NODE_NAME" --zone "$ZONE" --format '(disks[].source)' | grep "$DISK_NAME" > /dev/null; then
        echo "Attaching $DISK_NAME to $NODE_NAME"
        gcloud compute instances attach-disk "$NODE_NAME" --device-name=sdb --disk "$DISK_NAME" --zone "$ZONE"
    else
        echo "$DISK_NAME is already attached to $NODE_NAME"
    fi
    function create_wekaio_partition() {
        echo "--------------------------------------------"
        echo " Creating local filesystem on WekaIO volume "
        echo "--------------------------------------------"

        wekaiosw_device="/dev/sdb"
        if mount | grep -w $wekaiosw_device | grep -w /opt/weka; then
          echo "Weka volume is already mounted"
        else
          echo "Formatting and mounting Weka trace volume"
          mkfs.ext4 -L wekaiosw ${wekaiosw_device} || return 1
          mkdir -p /opt/weka || return 1
          mount $wekaiosw_device /opt/weka || return 1
          echo "LABEL=wekaiosw /opt/weka ext4 defaults 0 2" >>/etc/fstab
        fi
    }
    function prepare_weka_env() {
        echo "--------------- ENV ---------------"
        env
        echo "--------------- ENV ---------------"
        create_wekaio_partition || logger -s -t weka.install "Failed creating wekaio partition"
    }

    function start_weka_client() {
        prepare_weka_env
        if ! which weka; then
          echo "Installing agent from ${WEKA_DOWNLOADIP}"
          curl --fail --max-time 10 "http://${WEKA_DOWNLOADIP}:14000/dist/v1/install" | sh || logger -s -t weka.install "Failed installing agent from the first backend"
        else
          echo "Weka seems already installed, skipping agent install"
        fi
        mkdir -p ${WEKA_MOUNT}
        if mount | grep -w ${WEKA_MOUNT}; then
          echo "Weka filesystem seems already mounted on endpoint, skipping mount"
        else          
          mount -t wekafs ${WEKA_HOSTS}/${WEKA_FS} ${WEKA_MOUNT} -o remove_after_secs=${WEKA_CLIENTTIMEOUNT},num_cores=${WEKA_FRONTENDCORES},net=udp || logger -s -t weka.install "Error mounting filesystem"
        fi
    }

## Update to the name of the GKE cluster
GKE_CLUSTER_NAME=my-gke-cloud-name
GKE_METADATA_CLUSTER_NAME=$(curl -sS -H 'Metadata-Flavor: Google' 'http://metadata.google.internal/computeMetadata/v1/instance/?recursive=true&alt=json' | jq '.attributes."cluster-name"' -r)

if [ "$GKE_CLUSTER_NAME" != "GKE_METADATA_CLUSTER_NAME" ]; then
    echo "Instance does not belong to GKE cluster $GKE_CLUSTER_NAME. Skipping installation"
else
    echo "Instance belongs to GKE cluster, initializing Weka client installation"
    start_weka_client
fi

) >/root/startup.out 2>/root/startup.err