Suggest an editImprove this articleRefine the answer for “What is a container in Docker?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)A **container in Docker** is a running instance of a Docker image that operates as an isolated process on the host system. **Key point:** a container is an isolated process started from an image, which looks like a separate environment but shares the OS kernel with the host.Shown above the full answer for quick recall.Answer (EN)ImageA container in Docker is a running instance of a Docker image that operates as an isolated process on the host system. A container has its own filesystem, network, environment variables, and resources, but it uses the same operating system kernel as the host. ### **Key properties of a container** 1. **Isolation** A container's processes cannot see the processes and filesystem of other containers (namespaces). 2. **Its own filesystem** A container gets a filesystem based on the image, plus a top writable layer for its own changes. 3. **Lightness and speed** Containers start in a fraction of a second and consume fewer resources than virtual machines. 4. **Ephemerality** A container lives as long as its main process runs. After it stops, its state is usually not preserved (unless a volume is used). ### **Main idea** > A container is an isolated process started from an image, which looks like a separate environment but shares the OS kernel with the host. If needed, I can also briefly compare a container and a virtual machine in a single table.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.