https://webwork.blog/en/tags/serveradministration/Recent content in Serveradministration on WebWork BlogHugoen-USSat, 11 May 2024 16:33:06 +0000https://webwork.blog/en/server-migration-with-dd-over-ssh/Wed, 24 Apr 2024 20:37:06 +0000https://webwork.blog/en/server-migration-with-dd-over-ssh/Every so often I want to migrate a server "whole", as if I were pulling the disk out of the old server and plugging it into the new one. This is not only very convenient (no need to migrate each application's data individually), it is often faster than a manual migration.https://webwork.blog/en/cli-command-w-on-linux-unix/Tue, 28 Mar 2023 10:00:00 +0000https://webwork.blog/en/cli-command-w-on-linux-unix/Even with years of experience in IT you keep running into something new. Recently I came across the CLI command w. w gives a quick overview of which users are currently logged in to the system and what they are doing.https://webwork.blog/en/upgrade-debian-10-buster-to-debian-11-bullseye/Thu, 06 Jan 2022 21:32:42 +0000https://webwork.blog/en/upgrade-debian-10-buster-to-debian-11-bullseye/Debian releases a new stable version about every two years. The current version 11 (Bullseye) was released on August 14, 2021. Debian 10 (Buster) was released on July 6, 2019 and is expected to be updated until August 2022. After that, Debian 10 Buster is EOL ("https://webwork.blog/en/change-docker-subnets/Tue, 04 May 2021 20:34:25 +0000https://webwork.blog/en/change-docker-subnets/Docker is wasteful with IP subnets by default. On hosts with many networks, this sooner or later leads to the following error: Error response from daemon: could not find an available, non-overlapping IPv4 address pool among the defaults to assign to the network Looking at the created networks, the following pattern becomes apparent:https://webwork.blog/en/reinstall-contabo-vps-from-iso/Mon, 05 Apr 2021 13:00:21 +0000https://webwork.blog/en/reinstall-contabo-vps-from-iso/I recently rented a small storage VPS at Contabo. On my request (left as a comment during the order) it was provisioned in Munich, giving me a reasonable level of geo-redundancy against Nuremberg, where my other servers are hosted. The ~150 km between the two sites is already close to the BSI recommendation of 200 km for geo-redundant data centres — plenty for my needs.https://webwork.blog/en/server-snapshots-with-dd-over-ssh/Sat, 03 Apr 2021 15:53:18 +0000https://webwork.blog/en/server-snapshots-with-dd-over-ssh/A snapshot is an image of a disk or a system captured at a specific point in time. Depending on the environment, snapshots can be taken "online" (while the system is running) or "offline". Offline snapshots are generally preferable because they guarantee a consistent data set.https://webwork.blog/en/timezones-in-docker-containers/Tue, 23 Mar 2021 20:00:00 +0000https://webwork.blog/en/timezones-in-docker-containers/While reviewing logs from various Docker containers I ran into an issue: some containers were running with the host's local timezone (CET), others with UTC. While debugging I even spotted a third timezone in another container. The reason: every developer can pin an arbitrary timezone in their Dockerfile in 1–2 lines — definitely not a best practice, but it happened in one of the containers I was using.