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Servers troubleshooting

These records share a system family, but each page stays scoped to one symptom or failure state.

Cannot connect to the Docker daemonDocker documents two primary causes for “Cannot connect to the Docker daemon”: the daemon is not running, or the client is pointed at another unreachable daemon. On Linux, local Unix-socket permissions can also prevent a non-root user from connecting even when dockerd is healthy.

Editorial holdServers

Docker container DNS resolution not workingDocker containers normally inherit or proxy DNS based on the network they use. Default-bridge containers receive resolver settings derived from the host, while custom networks use Docker’s embedded DNS. Loopback resolvers such as 127.0.0.1 on the host are a common mismatch because that address means the container itself inside its network namespace.

Editorial holdDocker

Docker container keeps restarting in a loopA Docker container that repeatedly returns to a running/restarting state can be caused by its main process exiting while a restart policy relaunches it. First inspect the container state, restart count and policy; also note that Docker only activates a restart policy after the container has started successfully for at least 10 seconds.

Public launchDocker

Docker: no space left on deviceDocker can consume substantial storage through images, stopped containers, build cache and volumes. A no-space error may also come from the host filesystem or inode exhaustion. Docker provides docker system df to measure daemon usage and conservative prune commands that only remove categories you explicitly choose.

Editorial holdDocker

Docker published port is not reachableDocker containers are isolated by default, so a service is not reachable from outside the host until the correct container port is published with `-p` or `--publish`; a Dockerfile `EXPOSE` instruction alone does not create a host mapping. A localhost-only host bind can also intentionally prevent remote access.

Editorial holdDocker

Proxmox VM has no network or internet accessA Proxmox VE guest normally reaches the physical network through a Linux bridge such as vmbr0. If the VM has no network, verify the VM NIC, bridge attachment, host bridge uplink and guest IP configuration in that order.

Editorial holdProxmox VE