Apache Mesos is an open-source cluster manager that provides efficient resource isolation and sharing across distributed applications or frameworks. It can manage workloads on a dynamically shared pool of resources, making it an ideal platform for building complex distributed systems.
### Key Concepts
1. **Master Node**: The central coordinator in a Mesos cluster that manages the state of the cluster and resource allocation.
2. **Agent Node**: Nodes that run tasks. They report the availability of resources to the master node.
3. **Framework**: A distributed system that Mesos runs, which consists of a scheduler and one or more executors.
4. **Scheduler**: Part of a framework that registers with the master and receives resource offers.
5. **Executor**: Runs on agent nodes and executes the tasks assigned by the scheduler.
6. **Task**: The unit of work that is executed by Mesos on an agent node.
## Setting Up Apache Mesos
### Prerequisites
– Machines with a supported operating system (typically Linux).
– Admin/root privileges on the machines to install Mesos and its dependencies.
### Installation Steps
#### On Ubuntu
1. **Update Packages**:
“`sh
sudo apt-get update
“`
2. **Install Java**:
Mesos requires Java to run.
“`sh
sudo apt-get install -y openjdk-8-jdk
“`
3. **Add Mesos Repository**:
“`sh
echo “deb http://repos.mesosphere.com/ubuntu xenial main” | sudo tee /etc/apt/sources.list.d/mesosphere.list
“`
4. **Add Repository Key**:
“`sh
sudo apt-key adv –keyserver keyserver.ubuntu.com –recv E56151BF
“`
5. **Install Mesos**:
“`sh
sudo apt-get update
sudo apt-get install -y mesos
“`
### Configuring Mesos
#### Configuring Master Node
1. **Edit Mesos Master Configuration**:
“`sh
sudo nano /etc/mesos/zk
“`
Add the following line:
“`
zk://<master-ip>:2181/mesos
“`
2. **Start Mesos Master**:
“`sh
sudo service mesos-master start
“`
3. **Verify Master Node**:
Access the Mesos web UI at `http://<master-ip>:5050`.
#### Configuring Agent Nodes
1. **Edit Mesos Agent Configuration**:
“`sh
sudo nano /etc/mesos-slave/hostname
“`
Add the hostname or IP address of the agent node.
2. **Set Master URL on Agent**:
“`sh
echo zk://<master-ip>:2181/mesos | sudo tee /etc/mesos/zk
“`
3. **Start Mesos Agent**:
“`sh
sudo service mesos-slave start
“`
4. **Verify Agent Node**:
The agent should now appear in the Mesos web UI under agents.
### Running a Framework
Mesos can run various frameworks like Apache Marathon, Apache Spark, and others.
#### Example: Running Marathon
Marathon is a container orchestration platform for Mesos that can launch and manage Docker containers and other types of tasks.
1. **Install Marathon**:
“`sh
sudo apt-get install -y marathon
“`
2. **Configure Marathon**:
“`sh
sudo nano /etc/marathon/conf/master
“`
Add the following line:
“`
zk://<master-ip>:2181/mesos
“`
3. **Start Marathon**:
“`sh
sudo service marathon start
“`
4. **Verify Marathon**:
Access the Marathon web UI at `http://<master-ip>:8080`.
#### Deploying a Docker Container with Marathon
1. **Submit a Docker Application**:
Create a JSON file (`app.json`) with the following content:
“`json
{
“id”: “nginx”,
“cmd”: “sleep 10”,
“cpus”: 0.5,
“mem”: 512.0,
“instances”: 1,
“container”: {
“type”: “DOCKER”,
“docker”: {
“image”: “nginx”,
“network”: “BRIDGE”,
“portMappings”: [
{
“containerPort”: 80,
“hostPort”: 0,
“protocol”: “tcp”
}
]
}
}
}
“`
2. **Deploy the Application**:
“`sh
curl -X POST -H “Content-Type: application/json” http://<master-ip>:8080/v2/apps -d@app.json
“`
3. **Verify the Deployment**:
Check the Marathon UI for the status of your deployed application.
### Advanced Topics
1. **High Availability**:
– Deploy multiple Mesos master nodes for fault tolerance.
– Use ZooKeeper for leader election and state storage.
2. **Resource Management**:
– Understand roles and quotas for fine-grained resource allocation.
– Use reservation and dynamic reservations for specific frameworks.
3. **Security**:
– Implement authentication and authorization for frameworks and users.
– Use TLS for secure communication between nodes.
4. **Framework Development**:
– Develop custom frameworks using Mesos APIs.
– Implement custom schedulers and executors.
5. **Integration with Other Systems**:
– Integrate Mesos with Kubernetes using the Kubernetes-Mesos integration.
– Use DC/OS (Data Center Operating System) for enterprise-grade orchestration.
Conclusion
Apache Mesos is a powerful cluster manager that provides efficient resource isolation and sharing across distributed applications. Its flexibility and scalability make it suitable for managing large-scale, diverse workloads. By understanding the setup and configuration of Mesos, along with running frameworks like Marathon, you can effectively utilize Mesos for your container orchestration and cluster management needs.