doc/user/vtysh.rst

   1 .. _vty-shell:
   2
   3 *********
   4 VTY shell
   5 *********
   6
   7 .. program:: configure
   8
   9 *vtysh* provides a combined frontend to all FRR daemons in a single combined
  10 session. It is enabled by default at build time, but can be disabled through
  11 the :option:`--disable-vtysh` option to the configure script.
  12
  13 *vtysh* has a configuration file, :file:`vtysh.conf`. The location of that
  14 file cannot be changed from |INSTALL_PREFIX_ETC| since it contains options
  15 controlling authentication behavior. This file will also not be written by
  16 configuration-save commands, it is intended to be updated manually by an
  17 administrator with an external editor.
  18
  19 .. warning::
  20
  21    This also means the ``hostname`` and ``banner motd`` commands (which both do
  22    have effect for vtysh) need to be manually updated in :file:`vtysh.conf`.
  23
  24
  25 Permissions and setup requirements
  26 ==================================
  27
  28 *vtysh* connects to running daemons through Unix sockets located in
  29 |INSTALL_PREFIX_STATE|. Running vtysh thus requires access to that directory,
  30 plus membership in the |INSTALL_VTY_GROUP| group (which is the group that the
  31 daemons will change ownership of their sockets to).
  32
  33 To restrict access to FRR configuration, make sure no unauthorized users are
  34 members of the |INSTALL_VTY_GROUP| group.
  35
  36 PAM support (experimental)
  37 --------------------------
  38
  39 vtysh has working (but rather useless) PAM support. It will perform an
  40 "authenticate" PAM call using |PACKAGE_NAME| as service name. No other
  41 (accounting, session, password change) calls will be performed by vtysh.
  42
  43 Users using vtysh still need to have appropriate access to the daemons' VTY
  44 sockets, usually by being member of the |INSTALL_VTY_GROUP| group. If they
  45 have this membership, PAM support is useless since they can connect to daemons
  46 and issue commands using some other tool. Alternatively, the *vtysh* binary
  47 could be made SGID (set group ID) to the |INSTALL_VTY_GROUP| group.
  48
  49 .. warning::
  50
  51    No security guarantees are made for this configuration.
  52
  53
  54 .. index:: username USERNAME nopassword
  55 .. clicmd:: username USERNAME nopassword
  56
  57   If PAM support is enabled at build-time, this command allows disabling the
  58   use of PAM on a per-user basis. If vtysh finds that an user is trying to
  59   use vtysh and a "nopassword" entry is found, no calls to PAM will be made
  60   at all.
  61
  62
  63 .. _integrated-configuration-mode:
  64
  65 Integrated configuration mode
  66 =============================
  67
  68 Integrated configuration mode uses a single configuration file,
  69 :file:`frr.conf`, for all daemons. This replaces the individual files like
  70 :file:`zebra.conf` or :file:`bgpd.conf`.
  71
  72 :file:`frr.conf` is located in |INSTALL_PREFIX_ETC|. All daemons check for the
  73 existence of this file at startup, and if it exists will not load their
  74 individual configuration files. Instead, ``vtysh -b`` must be invoked to
  75 process :file:`frr.conf` and apply its settings to the individual daemons.
  76
  77 .. warning::
  78
  79    *vtysh -b* must also be executed after restarting any daemon.
  80
  81
  82 Configuration saving, file ownership and permissions
  83 ----------------------------------------------------
  84
  85 The :file:`frr.conf` file is not written by any of the daemons; instead *vtysh*
  86 contains the neccessary logic to collect configuration from all of the daemons,
  87 combine it and write it out.
  88
  89 .. warning::
  90
  91    Daemons must be running for *vtysh* to be able to collect their
  92    configuration. Any configuration from non-running daemons is permanently
  93    lost after doing a configuration save.
  94
  95 Since the *vtysh* command may be running as ordinary user on the system,
  96 configuration writes will be tried through *watchfrr*, using the ``write
  97 integrated`` command internally. Since *watchfrr* is running as superuser,
  98 *vtysh* is able to ensure correct ownership and permissions on
  99 :file:`frr.conf`.
 100
 101 If *watchfrr* is not running or the configuration write fails, *vtysh* will
 102 attempt to directly write to the file. This is likely to fail if running as
 103 unprivileged user; alternatively it may leave the file with incorrect owner or
 104 permissions.
 105
 106 Writing the configuration can be triggered directly by invoking *vtysh -w*.
 107 This may be useful for scripting. Note this command should be run as either the
 108 superuser or the FRR user.
 109
 110 We recommend you do not mix the use of the two types of files. Further, it is
 111 better not to use the integrated :file:`frr.conf` file, as any syntax error in
 112 it can lead to /all/ of your daemons being unable to start up. Per daemon files
 113 are more robust as impact of errors in configuration are limited to the daemon
 114 in whose file the error is made.
 115
 116 .. index:: service integrated-vtysh-config
 117 .. clicmd:: service integrated-vtysh-config
 118
 119 .. index:: no service integrated-vtysh-config
 120 .. clicmd:: no service integrated-vtysh-config
 121
 122    Control whether integrated :file:`frr.conf` file is written when
 123    'write file' is issued.
 124
 125    These commands need to be placed in :file:`vtysh.conf` to have any effect.
 126    Note that since :file:`vtysh.conf` is not written by FRR itself, they
 127    therefore need to be manually placed in that file.
 128
 129    This command has 3 states:
 130
 131
 132    service integrated-vtysh-config
 133       *vtysh* will always write :file:`frr.conf`.
 134
 135
 136    no service integrated-vtysh-config
 137       *vtysh* will never write :file:`frr.conf`; instead it will ask
 138       daemons to write their individual configuration files.
 139
 140    Neither option present (default)
 141       *vtysh* will check whether :file:`frr.conf` exists. If it does,
 142       configuration writes will update that file. Otherwise, writes are performed
 143       through the individual daemons.
 144
 145    This command is primarily intended for packaging/distribution purposes, to
 146    preset one of the two operating modes and ensure consistent operation across
 147    installations.
 148
 149 .. index:: write integrated
 150 .. clicmd:: write integrated
 151
 152    Unconditionally (regardless of ``service integrated-vtysh-config`` setting)
 153    write out integrated :file:`frr.conf` file through *watchfrr*. If *watchfrr*
 154    is not running, this command is unavailable.
 155
 156 .. warning::
 157
 158    Configuration changes made while some daemon is not running will be
 159    invisible to that daemon. The daemon will start up with its saved
 160    configuration (either in its individual configuration file, or in
 161    :file:`frr.conf`).  This is particularly troublesome for route-maps and
 162    prefix lists, which would otherwise be synchronized between daemons.
 163