Watchtower

Nowadays, most of us have containerized our services, and effectively managing and upgrading containers without affecting existing services is a critical issue. Two steps are required in the CI/CD process: first, packaging the environment as a Docker image and uploading it to the company’s private Docker registry; and second, after the upload is complete, possibly connecting to the machine via SSH, pulling the new image, and restarting the running service via the Graceful Shutdown mechanism. You can learn more about Graceful Shutdown in this article. I am going to introduces Watchtower, a brand new tool that automatically upgrades and updates running containers, allowing for further CD process streamlining. Developers only need to upload the Docker image, and the remote servers can update the running container automatically.

現在大家在部署服務肯定都已經容器化，而如何有效管理及升級容器不影響現有的服務，這就是一個重要的議題，然而在 CI/CD 的流程內，肯定有兩個步驟是必須的，第一就是將環境打包成 Docker Image 並上傳到公司內私有的 Docker Registry，以及上傳完畢後，也許透過 SSH 方式連上機器，並且拉取新的映像檔，再透過 Graceful Shutdown 機制重新啟動正在執行的服務。可以參考這篇了解什麼是 Graceful Shutdown。本篇就是要帶給大家一個全新的工具 Watchtower 用來自動升級更新執行中的容器，讓 CD 流程可以再簡化一步，開發者只要上傳完 Docker Image，遠方的伺服器就可以自動更新。