Caravela is a prototype for a Docker container orchestrator platform, inspired by the Docker Swarm and Kubernetes orchestrators, but with a fully decentralized architecture, resource discovery and scheduling algorithms, that are scalable in order to be deployed in a Edge Computing environment.
This work was developed in the context of my Masters Degree Thesis in Computer Science and Engineering @ Instituto Superior Técnico - University of Lisbon.
The main goal of the work was to test resource constrained scheduling requests evaluating its performance compared with centralized versions like Docker Swarm. In order to test its performance and scalability with thousands of nodes, Caravela-Sim was developed.
- Caravela has a P2P architecture (on top of the Chord P2P overlay). All the algorithms that run on top it are fully decentralized. Caravela is highly scalable and failure tolerant. It has no Single Point of Failure (SPoF).
- In the thesis we prove that for a network with 1,048,576 nodes providing resources, only Caravela could continue to operate offering a very good performance at all levels. After a few thousands nodes Docker Swarm master nodes would crush due to the load of requests.
- On contrary of Swarm user's can request the speed of the node's CPU where the container must be deployed.
- We extended the stack deployment of swarm to offer a request-level scheduling policy. A user can request in a stack deployment for a set of container to be deployed in the same node (e.g. due to low latency requirements), we called this co-location policy. User can also require that the containers must be spread over different nodes (e.g. due to resilience requirements), we called this spread policy. These proeprties are orthogonal to the system level scheduling policies (binpack and spread) that are supported in Docker Swarm and also in Caravela.
This project is a standalone middleware to orchestrate Docker containers, but it is highly inspired in the Docker, Swarm and Kubernetes projects so the APIs and the CLI mimic a small. but fundamental, subset of commands/features from that platforms. So it is easily migrate container's deployment for a Caravela instance.
Using the go tool chain it is possible to easily install Caravela in Go's local environment:
go get -u github.com/Strabox/caravela
The Makefile in the project's root makes all the necessary actions to easily compile, develop, test and deploy.
The only prerequisite to use the basic functionality of makefile is a properly configured golang environment/toolchain in the machine. The golang version used in project: 1.9.4.
There are two ways to build the project using the Makefile:
- Installing it in the golang environment
make install
- Building the project in the Makefile directory (creating the executable in the directory)
make build
A Caravela instance can be bootstrapped with a single node. The command necessary is the following one where <machine_ip> is the local ip address of the machine.
Important: This command should be issued to run as daemon because it will run all the Caravela's node operations!!
caravela create <machine_ip>
To enter and start supplying/use resources, the following command gets the job done. It is only needed to replace
<caravela_machine_ip> with the IP address of a machine that is already participating in a Caravela instance.
Important: This command should be issued to run as daemon because it will run all the Caravela's node operations!!
caravela join <caravela_machine_ip>
To deploy a container in Caravela that requires: a fast CPU (FastCPU: CPUClass = 1, SlowCPU: CPUClass = 0),
2 cores, 256MB of RAM and the port mapping 8080:80 the following command can be issued. The <container_image> parameter
should be replaced by a container's image allocated in DockerHub, e.g. strabox/caravela:latest.
caravela run -cpuClass 1 -cpus 2 -memory 256 -p 8080:80 <container_image>
To stop containers it is only necessary to replace <containerID_1> for the container's ID. The container's IDs
can be obtained with the command described in next section.
caravela container stop <containerID_1> <containerID_N>
To list all the container deployed in Caravela the following command outputs all of the information about each one.
caravela container ps
Use the GitHub issues tracker for exposing doubts, recommendations and questions.
This project is licensed under the GPL V3 License - see the LICENSE.md file for details.