How a container’s room gets out — Docker’s network modes compared with real namespace numbers, inside/outside pairing by @ifN, docker0 joined to the NIC by routing and NAT, CNM vs CNI and one CNI plugin call, VXLAN overlay, and one Go server knocked on from four places: another container, the host, another machine, and a container sharing its room.
Moving CI off GitHub-hosted runners after the organization ran out of included minutes — one spot EC2 instance with no inbound access, runners registered with a one-hour token sent over SSM, the key pair and long polling behind every job, the tools the image had to add back, why public repositories stay out, and the weak points that lead to the next post.
How a develop merge in each app repo becomes exactly one image in ECR — a role that can push to one repository only, a commit-SHA tag that never moves so the job checks before it builds, a build cache that silently never saved, and a digest a person still copies into the manifest by hand.
How Docker persists data outside containers: bind mounts vs named and anonymous volumes, how each behaves on mount and removal, and the node_modules trick.
설정을 컨테이너 이미지로 굽는다 — Docker 볼륨 연결이 Kubernetes에서 막히는 이유, Init 컨테이너와 emptyDir로 우회하는 법, 그리고 이 번거로운 패턴을 정말 써야 하는 순간.