Mesos allows dynamic sharing of cluster resources between Kubernetes and other first-class Mesos frameworks such as Hadoop, Spark, and Chronos. Mesos ensures applications from different frameworks running on your cluster are isolated and that resources are allocated fairly.
Running Kubernetes on Mesos allows you to easily move Kubernetes workloads from one cloud provider to another to your own physical datacenter.
This tutorial will walk you through setting up Kubernetes on a Mesos cluster on Google Cloud Plaform. It provides a step by step walk through of adding Kubernetes to a Mesos cluster and running the classic GuestBook demo application. The walkthrough presented here is based on the v0.4.x series of the Kubernetes-Mesos project, which itself is based on Kubernetes v0.11.0.
- Understanding of Apache Mesos
- Mesos cluster on Google Compute Engine
- Identify the Mesos master node external IP from Mesosphere cluster launch pad
- A VPN connection to the cluster.
Log into the master node over SSH, replacing the placeholder below with the correct IP address.
ssh jclouds@${ip_address_of_master_node}Build Kubernetes-Mesos.
$ git clone https://github.com/mesosphere/kubernetes-mesos k8sm
$ mkdir -p bin && sudo docker run --rm -v $(pwd)/bin:/target \
-v $(pwd)/k8sm:/snapshot -e GIT_BRANCH=release-0.4 \
mesosphere/kubernetes-mesos:buildSet some environment variables.
The internal IP address of the master is visible via the cluster details page on the Mesosphere launchpad, or may be obtained via hostname -i.
$ export servicehost=$(hostname -i)
$ export mesos_master=${servicehost}:5050
$ export KUBERNETES_MASTER=http://${servicehost}:8888Start etcd and verify that it is running:
$ sudo docker run -d --hostname $(uname -n) --name etcd -p 4001:4001 -p 7001:7001 coreos/etcd$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fd7bac9e2301 coreos/etcd:latest "/etcd" 5s ago Up 3s 2379/tcp, 2380/... etcdIt's also a good idea to ensure your etcd instance is reachable by testing it
curl -L http://$servicehost:4001/v2/keys/If connectivity is OK, you will see an output of the available keys in etcd (if any).
Start the kubernetes-mesos API server, controller manager, and scheduler on a Mesos master node:
$ ./bin/km apiserver \
--address=${servicehost} \
--mesos_master=${mesos_master} \
--etcd_servers=http://${servicehost}:4001 \
--portal_net=10.10.10.0/24 \
--port=8888 \
--cloud_provider=mesos \
--v=1 >apiserver.log 2>&1 &
$ ./bin/km controller-manager \
--master=$servicehost:8888 \
--mesos_master=${mesos_master} \
--v=1 >controller.log 2>&1 &
$ ./bin/km scheduler \
--address=${servicehost} \
--mesos_master=${mesos_master} \
--etcd_servers=http://${servicehost}:4001 \
--mesos_user=root \
--api_servers=$servicehost:8888 \
--v=2 >scheduler.log 2>&1 &Also on the master node, we'll start up a proxy instance to act as a public-facing service router, for testing the web interface a little later on.
$ sudo ./bin/km proxy \
--bind_address=${servicehost} \
--etcd_servers=http://${servicehost}:4001 \
--logtostderr=true >proxy.log 2>&1 &Disown your background jobs so that they'll stay running if you log out.
$ disown -aInteract with the kubernetes-mesos framework via kubectl:
$ bin/kubectl get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS$ bin/kubectl get services # your service IPs will likely differ
NAME LABELS SELECTOR IP PORT
kubernetes component=apiserver,provider=kubernetes <none> 10.10.10.2 443
kubernetes-ro component=apiserver,provider=kubernetes <none> 10.10.10.1 80Lastly, use the Mesos CLI tool to validate the Kubernetes scheduler framework has been registered and running:
$ mesos state | grep "Kubernetes"
"name": "Kubernetes",Or, look for Kubernetes in the Mesos web GUI. You can get there by clicking the
Mesos logo on the Mesosphere launchpad page, or by pointing your browser to
http://${mesos_master}. Make sure you have an active VPN connection.
Go to the Frameworks tab, and look for an active framework named "Kubernetes".
Write a JSON pod description to a local file:
$ cat <<EOPOD >nginx.json
{ "kind": "Pod",
"apiVersion": "v1beta1",
"id": "nginx-id-01",
"desiredState": {
"manifest": {
"version": "v1beta1",
"containers": [{
"name": "nginx-01",
"image": "nginx",
"ports": [{
"containerPort": 80,
"hostPort": 31000
}],
"livenessProbe": {
"enabled": true,
"type": "http",
"initialDelaySeconds": 30,
"httpGet": {
"path": "/index.html",
"port": "8081"
}
}
}]
}
},
"labels": {
"name": "foo"
} }
EOPODSend the pod description to Kubernetes using the kubectl CLI:
$ bin/kubectl create -f nginx.json
nginx-id-01Wait a minute or two while dockerd downloads the image layers from the internet.
We can use the kubectl interface to monitor the status of our pod:
$ bin/kubectl get pods
POD IP CONTAINER(S) IMAGE(S) HOST LABELS STATUS
nginx-id-01 172.17.5.27 nginx-01 nginx 10.72.72.178/10.72.72.178 cluster=gce,name=foo RunningVerify 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.
Following the instructions from the kubernetes-mesos examples/guestbook:
$ export ex=k8sm/examples/guestbook
$ bin/kubectl create -f $ex/redis-master.json
$ bin/kubectl create -f $ex/redis-master-service.json
$ bin/kubectl create -f $ex/redis-slave-controller.json
$ bin/kubectl create -f $ex/redis-slave-service.json
$ bin/kubectl create -f $ex/frontend-controller.json
$ cat <<EOS >/tmp/frontend-service
{
"id": "frontend",
"kind": "Service",
"apiVersion": "v1beta1",
"port": 9998,
"selector": {
"name": "frontend"
},
"publicIPs": [
"${servicehost}"
]
}
EOS
$ bin/kubectl create -f /tmp/frontend-serviceWatch your pods transition from Pending to Running:
$ watch 'bin/kubectl get pods'Review your Mesos cluster's tasks:
$ mesos ps
TIME STATE RSS CPU %MEM COMMAND USER ID
0:00:05 R 41.25 MB 0.5 64.45 none root 0597e78b-d826-11e4-9162-42010acb46e2
0:00:08 R 41.58 MB 0.5 64.97 none root 0595b321-d826-11e4-9162-42010acb46e2
0:00:10 R 41.93 MB 0.75 65.51 none root ff8fff87-d825-11e4-9162-42010acb46e2
0:00:10 R 41.93 MB 0.75 65.51 none root 0597fa32-d826-11e4-9162-42010acb46e2
0:00:05 R 41.25 MB 0.5 64.45 none root ff8e01f9-d825-11e4-9162-42010acb46e2
0:00:10 R 41.93 MB 0.75 65.51 none root fa1da063-d825-11e4-9162-42010acb46e2
0:00:08 R 41.58 MB 0.5 64.97 none root b9b2e0b2-d825-11e4-9162-42010acb46e2The number of Kubernetes pods listed earlier (from bin/kubectl get pods) should equal to the number active Mesos tasks listed the previous listing (mesos ps).
Next, determine the internal IP address of the front end service portal:
$ bin/kubectl get services
NAME LABELS SELECTOR IP PORT
kubernetes component=apiserver,provider=kubernetes <none> 10.10.10.2 443
kubernetes-ro component=apiserver,provider=kubernetes <none> 10.10.10.1 80
redismaster <none> name=redis-master 10.10.10.49 10000
redisslave name=redisslave name=redisslave 10.10.10.109 10001
frontend <none> name=frontend 10.10.10.149 9998Interact with the frontend application via curl using the front-end service IP address from above:
$ curl http://${frontend_service_ip_address}:9998/index.php?cmd=get\&key=messages
{"data": ""}Or via the Redis CLI:
$ sudo apt-get install redis-tools
$ redis-cli -h ${redis_master_service_ip_address} -p 10000
10.233.254.108:10000> dump messages
"\x00\x06,world\x06\x00\xc9\x82\x8eHj\xe5\xd1\x12"Or interact with the frontend application via your browser, in 2 steps:
First, open the firewall on the master machine.
# determine the internal port for the frontend service portal
$ sudo iptables-save|grep -e frontend # -- port 36336 in this case
-A KUBE-PORTALS-CONTAINER -d 10.10.10.149/32 -p tcp -m comment --comment frontend -m tcp --dport 9998 -j DNAT --to-destination 10.22.183.23:36336
-A KUBE-PORTALS-CONTAINER -d 10.22.183.23/32 -p tcp -m comment --comment frontend -m tcp --dport 9998 -j DNAT --to-destination 10.22.183.23:36336
-A KUBE-PORTALS-HOST -d 10.10.10.149/32 -p tcp -m comment --comment frontend -m tcp --dport 9998 -j DNAT --to-destination 10.22.183.23:36336
-A KUBE-PORTALS-HOST -d 10.22.183.23/32 -p tcp -m comment --comment frontend -m tcp --dport 9998 -j DNAT --to-destination 10.22.183.23:36336
# open up access to the internal port for the frontend service portal
$ sudo iptables -A INPUT -i eth0 -p tcp -m state --state NEW,ESTABLISHED -m tcp \
--dport ${internal_frontend_service_port} -j ACCEPTNext, add a firewall rule in the Google Cloud Platform Console. Choose Compute > Compute Engine > Networks, click on the name of your mesosphere-* network, then click "New firewall rule" and allow access to TCP port 9998.
Now, you can visit the guestbook in your browser!
