Using Operational Commands to Monitor a Device

The following table lists some standard directories on a Juniper Networks device.

Table 1: Directories on the Device

DIrectory	Description
/config	This directory is located on the device’s internal flash drive. It contains the active configuration (juniper.conf) and rollback files 1, 2, and 3.
/var/db/config	This directory is located on the device’s hard drive and contains rollback files 4 through 49.
/var/tmp	This directory is located on the device’s hard drive. It holds core files from the various processes on the Routing Engines. Core files are generated when a particular process crashes. Juniper Networks engineers use these core files to diagnose the cause of the failure.
/var/log	This directory is located on the device’s hard drive. It contains files generated by both the device’s logging function and the traceoptions command.
/var/home	This directory is located on the device’s hard drive. It contains a subdirectory for each configured user on the device. These individual user directories are the default file location for many software commands.
/altroot	This directory is located on the device’s hard drive and contains a copy of the root file structure from the internal flash drive. This directory is used in certain disaster recovery modes where the internal flash drive is not operational.
/altconfig	This directory is located on the device’s hard drive and contains a copy of the /config file structure from the internal flash drive. This directory is also used in certain disaster recovery modes when the internal flash drive is not operational.

You can view the device’s directory structure as well as individual files by issuing the file command in operational mode.

1. To get help about the file command, enter file ?:

   Help shows that the file command includes several options for manipulating files.

2. Use the list option to see the directory structure of the device. For example, to show the files located in your home directory on the device:

   The default directory for the file list command is the home directory of the user logged in to the device. In fact, the user’s home directory is the default directory for most of the commands requiring a filename.

3. To view the contents of other file directories, specify the directory location. For example:

4. You can also use the device’s context-sensitive help system to locate a directory. For example:

5. You can also display the contents of a file. For example:

You can include a filename in CLI commands and configuration statements such as these:

• file copy
• file archive,
• load,
• save
• set system login user
• username
• authentication
• load-key-file
• request system software add

On a routing matrix, you can include chassis information as part of the filename (for example, lcc0, lcc0-re0, or lcc0-re1).

You can specify a filename or URL in one of the following ways:

• filename—File in the user’s current directory on the local flash drive. You can use wildcards to specify multiple source files or a single destination file. Neither HTTP nor FTP supports wildcards.

  Note:

  Only the file (compare | copy | delete | list | rename | show) commands support wildcards. When you issue the file show command with a wildcard, the command must resolve to one filename.

• path/filename—File on the local flash disk.

• /var/filename or /var/path/filename—File on the local hard disk.

  You can also specify a file on a local Routing Engine for a specific T640 router on a routing matrix:

• a:filename or a:path/filename—File on the local drive. The default path is / (the root-level directory). The removable media can be in MS-DOS or UNIX (UFS) format.

• hostname:/path/filename, hostname:filename, hostname:path/filename, or scp://hostname/path/filename—File on an scp/ssh client. This form is not available in the worldwide version of the operating system. The default path is the user’s home directory on the remote system. You can also specify hostname as username@hostname.

• ftp://hostname/path/filename—File on an FTP server. You can also specify hostname as username@hostname or username:password@hostname. The default path is the user’s home directory.

  To specify an absolute path, the path must start with %2F; for example, ftp://hostname/%2Fpath/filename.

  To have the system prompt you for the password, specify prompt in place of the password. If a password is required, and you do not specify the password or prompt, an error message is displayed:

• http://hostname/path/filename—File on an HTTP server. You can also specify hostname as username@hostname or username:password@hostname. If a password is required and you omit it, you are prompted for it.

• re0:/path/filename or re1:/path/filename—File on a local Routing Engine.

  You can also specify a file on a local Routing Engine for a specific T640 router on a routing matrix:

To verify system operation or to begin diagnosing an error condition, you may need to display information about software processes running on the device.

To show software processes:

1. Make sure you are in operational mode.

2. Enter the show system processes extensive command. This command shows the CPU utilization on the device and lists the processes in order of CPU utilization.

The following table lists and describes the output fields included in this example. The fields are listed in alphabetical order.

Table 2: The show system process extensive Command Output Fields

Field	Description
COMMAND	Command that is running.
last pid	Last process identifier assigned to the process.
load averages	Three load averages, followed by the current time.
Mem	Information about physical and virtual memory allocation.
NICE	UNIX “nice” value. The nice value allows a process to change its final scheduling priority.
PID	Process identifier.
PRI	Current kernel scheduling priority of the process. A lower number indicates a higher priority.
processes	Number of existing processes and the number of processes in each state (sleeping, running, starting, zombies, and stopped).
RES	Current amount of resident memory, in KB.
SIZE	Total size of the process (text, data, and stack), in KB.
STATE	Current state of the process (sleep, wait, run, idle, zombi, or stop).
Swap	Information about physical and virtual memory allocation.
USERNAME	Owner of the process.
WCPU	Weighted CPU usage.

To correct an error condition, you might need to restart a software process running on the device. You can use the restart command to force a restart of a software process.

CAUTION:

Do not restart a software process unless specifically asked to do so by your Juniper Networks customer support representative. Restarting a software process during normal operation of a device can interrupt packet forwarding and cause data loss.

To restart a software process:

1. Make sure you are in operational mode.

2. Enter the following command:

   • process-name is the name of the process that you want to restart. For example, routing or class-of-service. You can use the command completion feature of the system to see a list of software processes that you can restart using this command.

   • The option gracefully restarts the software process after performing clean-up tasks.

   • The option immediately restarts the software process without performing any clean-up tasks.

   • The option soft rereads and reactivates the configuration without completely restarting the software processes. For example, BGP peers stay up and the routing table stays constant.

Note:

The gracefully, immediately, and soft options for the restart command are optional and not required for executing the command.

The following example shows how to restart the routing process:

When a process restarts, the process identifier (PID) is updated.

CAUTION:

To avoid possible damage to the file system and to prevent data loss, you must always shut down the software gracefully before powering off the device.

You must stop the software on a device through a direct console connection, not through the network. As the software shuts down, the network will go down, and if you were connected that way, you will not see the results output.

To stop the software:

1. Make sure you are in operational mode.

2. Enter the request system halt command. This command stops all system processes and halts the operating system. For example:

After a software upgrade or to recover (occasionally) from an error condition, you must reboot the software. As with the shutdown command, you must reboot through a direct console connection otherwise you will not see the command output when the network goes down during the reboot process.

To reboot the software:

1. Make sure you are in operational mode.

2. Enter the request system reboot command. This command displays the final stages of the system shutdown and executes the reboot. Reboot requests are recorded to the system log files, which you can view with the show log messages command. For example: