Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Documentation for /proc/sys/user/* kernel version 4.9.0 2 (c) 2016 Eric Biederman <ebiederm@xmission.com> 3 4 ============================================================== 5 6 This file contains the documentation for the sysctl files in 7 /proc/sys/user. 8 9 The files in this directory can be used to override the default 10 limits on the number of namespaces and other objects that have 11 per user per user namespace limits. 12 13 The primary purpose of these limits is to stop programs that 14 malfunction and attempt to create a ridiculous number of objects, 15 before the malfunction becomes a system wide problem. It is the 16 intention that the defaults of these limits are set high enough that 17 no program in normal operation should run into these limits. 18 19 The creation of per user per user namespace objects are charged to 20 the user in the user namespace who created the object and 21 verified to be below the per user limit in that user namespace. 22 23 The creation of objects is also charged to all of the users 24 who created user namespaces the creation of the object happens 25 in (user namespaces can be nested) and verified to be below the per user 26 limits in the user namespaces of those users. 27 28 This recursive counting of created objects ensures that creating a 29 user namespace does not allow a user to escape their current limits. 30 31 Currently, these files are in /proc/sys/user: 32 33 - max_cgroup_namespaces 34 35 The maximum number of cgroup namespaces that any user in the current 36 user namespace may create. 37 38 - max_ipc_namespaces 39 40 The maximum number of ipc namespaces that any user in the current 41 user namespace may create. 42 43 - max_mnt_namespaces 44 45 The maximum number of mount namespaces that any user in the current 46 user namespace may create. 47 48 - max_net_namespaces 49 50 The maximum number of network namespaces that any user in the 51 current user namespace may create. 52 53 - max_pid_namespaces 54 55 The maximum number of pid namespaces that any user in the current 56 user namespace may create. 57 58 - max_user_namespaces 59 60 The maximum number of user namespaces that any user in the current 61 user namespace may create. 62 63 - max_uts_namespaces 64 65 The maximum number of user namespaces that any user in the current 66 user namespace may create.