First of all, let me share with you my test environment:
(1) CentOS 7.1.1503 (nodes = hdp1, hdp2 and hdp3)
(2) HDP 2.3.2 (re-using the installed Zookeeper)
(3) Docker v1.8.3
(4) golang 1.4.2
(5) etcd 2.1.1
The official documentation for Kubernetes-Mesos integration can be found
here. It uses Google Compute Engine (GCE), but this blog entry will share about deploying Kubernetes-Mesos integration on a local cluster.
Ok, let's begin...
Prerequisites
(1) A working local Mesos cluster
NOTE: To build one, please refer to
this.
(2) Install Docker on
ALL nodes.
(a) Make sure yum has access to the
official Docker repository.
(b) Execute "yum install docker-engine"
(c) Enable docker.service with "systemctl enable docker.service"
(d) Start docker.service with "systemctl start docker.service"
(3) Install "golang" on the node which you wish to install and deploy Kubernetes-Mesos integration.
(a) Execute "yum install golang"
(4) Install "etcd" on a selected node (preferably on the node that host the Kubernetes-Mesos integration for testing purposes).
(a) Execute "yum install etcd"
(b) Amend file "/usr/lib/systemd/system/etcd.service" (see below):
[FROM]
ExecStart=/bin/bash -c "GOMAXPROCS=$(nproc) /usr/bin/etcd"
[TO]
ExecStart=/bin/bash -c "GOMAXPROCS=$(nproc) /usr/bin/etcd --listen-client-urls http://0.0.0.0:4001 --advertise-client-urls http://[node_ip]:4001"
WHERE
[node_ip] = IP Address of the node (hostname -i)
(c) Reload systemctl daemon with "systemctl daemon-reload".
(d) Enable etcd.service with "systemctl enable etcd.service".
(e) Start etcd.service with "systemctl start etcd.service".
***
Build Kubernetes-Mesos
NOTE: Execute the following on the node selected to host the Kubernetes-Mesos integration.
cd [directory to install kubernetes-mesos]
git clone https://github.com/kubernetes/kubernetes
cd kubernetes
export KUBERNETES_CONTRIB=mesos
make
***
Export environment variables
(1) Export the following environment variables:
export KUBERNETES_MASTER_IP=$(hostname -i)
export KUBERNETES_MASTER=http://${KUBERNETES_MASTER_IP}:8888
export MESOS_MASTER=[zk://.../mesos]
export PATH="[directory to install kubernetes-mesos]/_output/local/go/bin:$PATH"
WHERE
[zk://.../mesos] = URL of the zookeeper nodes (Eg. zk://hdp1:2181,hdp2:2181,hdp3:2181/mesos)
[directory to install kubernetes-mesos] = Directory used to perform "git clone" (see "Build Kubernetes-Mesos" above).
(2) Amend .bash_profile to make the variables permanent.
(3) Remember to source the .bash_profile file after amendment (. ~/.bash_profile).
***
Configure and start Kubernetes-Mesos service
(1) Create a cloud config file mesos-cloud.conf in the current directory with the following contents:
$ cat <<EOF >mesos-cloud.conf
[mesos-cloud]
mesos-master = ${MESOS_MASTER}
EOF
NOTE:
If you have not set ${MESOS_MASTER}, it should be like (example) "zk://hdp1:2181,hdp2:2181,hdp3:2181/mesos".
(2) Create a script to start all the relevant components (API server, controller manager, and scheduler):
km apiserver \
--address=${KUBERNETES_MASTER_IP} \
--etcd-servers=http://${KUBERNETES_MASTER_IP}:4001 \
--service-cluster-ip-range=10.10.10.0/24 \
--port=8888 \
--cloud-provider=mesos \
--cloud-config=mesos-cloud.conf \
--secure-port=0 \
--v=1 >apiserver.log 2>&1 &
sleep 3
km controller-manager \
--master=${KUBERNETES_MASTER_IP}:8888 \
--cloud-provider=mesos \
--cloud-config=./mesos-cloud.conf \
--v=1 >controller.log 2>&1 &
sleep 3
km scheduler \
--address=${KUBERNETES_MASTER_IP} \
--mesos-master=${MESOS_MASTER} \
--etcd-servers=http://${KUBERNETES_MASTER_IP}:4001 \
--mesos-user=root \
--api-servers=${KUBERNETES_MASTER_IP}:8888 \
--cluster-dns=10.10.10.10 \
--cluster-domain=cluster.local \
--contain-pod-resources=false \
--v=2 >scheduler.log 2>&1 &
NOTE:
Since CentOS uses systemd, you will hit this
issue. Hence, you need to add the "--contain-pod-resources=false" to the scheduler (in bold above).
(3) Give execute permission to the script (chmod 700 <script>).
(4) Execute the script.
***
Validate Kubernetes-Mesos services
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
# NOTE: Your service IPs will likely differ
$ kubectl get services
NAME LABELS SELECTOR IP(S) PORT(S)
k8sm-scheduler component=scheduler,provider=k8sm <none> 10.10.10.113 10251/TCP
kubernetes component=apiserver,provider=kubernetes <none> 10.10.10.1 443/TCP
(4) Lastly, look for Kubernetes in the Mesos web GUI by pointing your browser to http://[mesos-master-ip:port]. Go to the Frameworks tab, and look for an active framework named "Kubernetes".
 |
| Kubernetest framework is registered with Mesos |
***
Let's spin up a pod
(1) Write a JSON pod description to a local file:
$ cat <<EOPOD >nginx.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
EOPOD
(2) Send the pod description to Kubernetes using the "kubectl" CLI:
$ kubectl create -f ./nginx.yaml
pods/nginx
 |
| Submitted pod through kubectl |
(3) Wait a minute or two while Docker downloads the image layers from the internet. We can use the kubectl interface to monitor the status of our pod:
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx 1/1 Running 0 14s
(4) Verify that the pod task is running in the Mesos web GUI. Click on the Kubernetes framework. The next screen should show the running Mesos task that started the Kubernetes pod.
 |
| Mesos WebGUI shows active Kubernetes task |
 |
| Mesos WebGUI shows that the Kubernetes task is RUNNING |
 |
| Click through "Sandbox" link of the task to get to the "executor.log" |
 |
| An example of "executor.log" |
 |
| Connected to the node where the container is running |
Getting Kubernetes to work on Mesos can be rather challenging at this point of time.
However, it is possible and hopefully, over time, Kubernetes-Mesos integration can work seamlessly.
Have fun!
