Jenkins is a friend of mine. 😀

There are not much space for Jenkins competitors for now from my point of view. With declarative pipelines now in place, its super easy to maintain them and create new ones(altho I prefer scripted still). Self-hosted, free, huge community makes it the top choice so honestly for me it was an easy pick.

We develop rapidly with docker-compose orchestrated services, however, for production - we utilise the very best ideas that Kubernetes has to offer: SCALE! We can scale when needed, setting a maximum and minimum level of nodes for each application layer - scaling only when the load balancer needs it. This allowed us to reduce our devops costs by 40% whilst also maintaining an SLA of 99.87%.

Within our deployment pipeline, we have a need to deploy to multiple customer environments, and manage secrets specifically in a way that integrates well with AWS, Kubernetes Secrets, Terraform and our pipelines ourselves.

Jenkins offered us the ability to choose one of a number of credentials/secrets management approaches, and models secrets as a more dynamic concept that GitHub Actions provided.

Additionally, we are operating Jenkins within our development Kubernetes cluster as a kind of system-wide orchestrator, allowing us to use Kubernetes pods as build agents, avoiding the ongoing direct costs associated with GitHub Actions minutes / per-user pricing. Obviously as a consequence we take on the indirect costs of maintain Jenkins itself, patching it, upgrading etc. However our experience with managing Jenkins via Kubernetes and declarative Jenkins configuration has led us to believe that this cost is small, particularly as the majority of actual building and testing is handled inside docker containers and Kubernetes, alleviating the need for less supported plugins that may make Jenkins administration more difficult.

Our whole DevOps stack consists of the following tools:

• GitHub (incl. GitHub Pages/Markdown for Documentation, GettingStarted and HowTo's) for collaborative review and code management tool
• Respectively Git as revision control system
• SourceTree as Git GUI
• Visual Studio Code as IDE
• CircleCI for continuous integration (automatize development process)
• Prettier / TSLint / ESLint as code linter
• SonarQube as quality gate
• Docker as container management (incl. Docker Compose for multi-container application management)
• VirtualBox for operating system simulation tests
• Kubernetes as cluster management for docker containers
• Heroku for deploying in test environments
• nginx as web server (preferably used as facade server in production environment)
• SSLMate (using OpenSSL) for certificate management
• Amazon EC2 (incl. Amazon S3) for deploying in stage (production-like) and production environments
• PostgreSQL as preferred database system
• Redis as preferred in-memory database/store (great for caching)

The main reason we have chosen Kubernetes over Docker Swarm is related to the following artifacts:

• Key features: Easy and flexible installation, Clear dashboard, Great scaling operations, Monitoring is an integral part, Great load balancing concepts, Monitors the condition and ensures compensation in the event of failure.
• Applications: An application can be deployed using a combination of pods, deployments, and services (or micro-services).
• Functionality: Kubernetes as a complex installation and setup process, but it not as limited as Docker Swarm.
• Monitoring: It supports multiple versions of logging and monitoring when the services are deployed within the cluster (Elasticsearch/Kibana (ELK), Heapster/Grafana, Sysdig cloud integration).
• Scalability: All-in-one framework for distributed systems.
• Other Benefits: Kubernetes is backed by the Cloud Native Computing Foundation (CNCF), huge community among container orchestration tools, it is an open source and modular tool that works with any OS.

Jenkins is a pretty flexible, complete tool. Especially I love the possibility to configure jobs as a code with Jenkins pipelines.

CircleCI is well suited for small projects where the main task is to run continuous integration as quickly as possible. Travis CI is recommended primarily for open-source projects that need to be tested in different environments.

And for something a bit larger I prefer to use Jenkins because it is possible to make serious system configuration thereby different plugins. In Jenkins, I can change almost anything. But if you want to start the CI chain as soon as possible, Jenkins may not be the right choice.