NamespaceWhat it isolatesWhat the process seesPIDProcess IDsOwn process tree, starts at PID 1MountFilesystem mount pointsOwn mount table, can have different rootNetworkNetwork interfaces, routingOwn interfaces, IP addresses, portsUserUID/GID mappingCan be root inside, nobody outsideUTSHostnameOwn hostnameIPCSysV IPC, POSIX message queuesOwn shared memory, semaphoresCgroupCgroup root directoryOwn cgroup hierarchyTimeSystem clocks (monotonic, boot)Own system uptime and clock offsetsNamespaces are what Docker containers use. When you run a container, it gets its own PID namespace (cannot see host processes), its own mount namespace (own filesystem view), its own network namespace (own interfaces), and so on.
A so-called "planetary nebula" is a confusing misnomer because these clouds have nothing to do with planets. As a medium-size star nears the end, it puffs out into a red giant — about 100 to 1,000 times its original size — eventually engulfing the space around it, including any nearby worlds.。业内人士推荐同城约会作为进阶阅读
，这一点在搜狗输入法2026中也有详细论述
Paul Hennesy/Anadolu via Getty Images。51吃瓜对此有专业解读
Otherwise simply advance the cursor: