Script to Monitor and Restart Jail

[dnjordman]

First, apologies for what I know is an extremely noob question. I'm running a jail on my FreeNAS box that for some unknown reason loses its internet connection periodically. Manually restarting the jail fixes the issue. I'm trying to write a script I can call via cron to check the status of the jail and restart it automatically if need be. Here's what I have for the script:

Code:

#!/bin/bash                                                                    
# MyJail Checker                                                            
                                                                               
mj_con_string='Current IPv4 Connections: '                                     
                                                                               
mj_status=$(/usr/local/bin/warden details myjail | grep -i                  
"$mj_con_string[0-9]\+")                                                       
                                                                               
mj_con_num="${mj_status//$mj_con_string}"                                      
                                                                               
if [ "$mj_con_num" = "0" ]; then                                               
        echo restarting myjail
        /usr/local/bin/warden stop myjail && /usr/local/bin/warden start myjail
else                                                                           
        echo myjail looks fine                                              
fi

In this example, the jail's name is "myjail." When the number of connections drops to zero, that's when I know it needs to be restarted. When I run this script, I get this output:

Code:

Usage: grep [OPTION]... PATTERN ...                                      
Try `grep --help' for more information.                                        
/usr/bin/mj_check: line 8: Current IPv4 Connections: [0-9]\+: command not found
myjail looks fine  

Something's clearly not right with my grep command, but I just don't know what it is. I've searched around and haven't really been able to figure out what I'm doing wrong. Any help would be greatly appreciated.

 

[DrKK]

I'm about to go to bed, so I am not going to dissect the grep command, but I can tell you, I get PRECISELY this behavior if my router/switch resets. If I reboot the router, I will need to manually restart all of the jails, because they will all lose connection, and only the FreeNAS appliance IP itself will be accessible after such a reboot.

 

[rogerh]

I think the problem is that your "grep -i" argument has ended up on a new line. The brackets alone aren't sufficient for the shell to ignore the new line. Either put the ' "$mj_con_string[0-9]\+")' on the same line or escape the newline character with a "\" at the very end of the line that "grep -i" is on, after any white space.