I'm a beginner in Proxmox.
Actually, everything was working perfectly fine until I installed 2 additional hard disks in my server.
All of a sudden, I had an error mentioning that CPU was blocked for more then 25sec... I restarted and the server and now it's telling me that I'm in Emergency Mode...
I have 2 options:
Give root password for maintenance
press Control-D to continue
Control-D:
When I'm pressing control-D to continue it's saying: Reloading system manager configuration, starting default target. Then it starts asking the password for maintenance or press control-d... again and again...
Root Password
Is is the same password as the one I'm using to connect to the GUI? If that's the case, since I have a very long password with special characters, I need to see what I'm typing which is not the case by default... How can I check that?
What if I remove the 2 new additional hard disks ? Should it start normally ? Or I will still be in emergency mode ?
It's the same password and no, you cannot see what you are typing.
Remove drives, it should boot normally. You need to check and edit /etc/fstab so it's not using new drives as root. Maybe these two disks are not empty?
Related
I have a problem reconnecting to ISPF. After the TSO/E LOGON screen, the screen on the attached picture shows and says that logon reconnection is successful, but it doesn't proceed to ISPF. If I type any commands, ISPF, logoff, etc. it locks.
Make sure you are connecting with the same terminal settings(mod5, mod2, etc).
Sometime you need to use PA2 to force a rebuild of the current panel. If you disconnected while running a CLIST/EXEC/program, then you might need to ATTN out of it.
It could have been that you were in a process that was looping or hung, and you were simply reconnected to that looping/hanging process. Next time, try the ATTN key. I have seen some installations set up the logon screen/process where if you do not choose RECONNECT, your still-active prior session will be terminated prior to logging you on. This is a nice setup, especially for hang situations like you were probably in.
Let's state a situation:
I have the possibility to run arbitrary commands on a server as an unprivileged user, through "unconventional means".
I do not have the possibility to login using ssh to that server, either as my unprivileged user or anything else. So I do not have currently a CLI allowing me to run any commands I would like in a "normal" way.
I can ping that server and nothing prevents me to connect to arbitrary ports.
I still would like to have a command line to allow me to run arbitrary command as i wish on that server.
Theoretically nothing would prevent me to launch any program as my unprivileged user, including one that would open a port, allow some remote user to connect to it and just forward any commands to bash, returning the result. I just don't know any good program to do that.
So, does any one know? I looked at ways to launch ssh_server as an unprivileged user but some users reported that recent versions of ssh_server do not allow that anymore. Actually I don't even need ssh specifically, any way to get a working CLI would do the trick. Even a crappy node.js program launching an http server would work, as long as I have a CLI (... and it's not excessively crappy, the goal is to have a clean CLI, not something that bugs every two characters).
In case you would ask why I would like to do that, it's not related to anything illegal ^^. I just have to work with a very crappy Jenkins server for which I'm not allowed to have direct access to its agents. Whoever is responsible for that server doesn't give a sh** about its users' needs so we have to use hacky solutions just to have some diagnostic data about that server (like ram, cpu and disk usage, installed programs, etc...). Having a CLI that I can launch some time instead of altering a build configuration and waiting 20 minutes to have an answer about what's going on would really help.
Thanks in advance for any answer.
So do you have shell access to the server at least once? E.g., during the single day of the month when you are physically present at the site of your client or the outsourcing contractor?
And if you have shell access then, can you or your sysmin install Cockpit?
It listens on port 9090.
You can then use the credentials of your local user and open a terminal window in your browser. See sidebar item "Terminal" on the screenshots of the cockpit homepage.
According to the documentation
Cockpit has no special privileges and doesn’t run as root. It creates a session as the logged in user and has the same permissions as that user.
I have done some research and it seems that this is a common problem and I just installed the latest Ubuntu today on my computer. However, for some reason when I click the shut down button it always restarts instead of shutting down. I have already tried all those terminal commands to shut it down, but those don't work either. It always restarts itself.. Is there anyway I can power it off without having to resort to manually holding my computer's power button?
Edit:
I tried those grub update things too, but the commands I get from the forums don't seem to work anyways so that's also one solution that wouldn't work.
try this one on the terminal:
sudo init 0
I have created a web application where user can run Java code in the browser.
I am using chroot for executing user submitted code in the web server.
In the chroot script I am doing mounting and then unmounting some required directories.
this works very well normally but when I fire that executing requests in a row like
20-30 requests, then for some response I am getting this message /bin/su: user XXX does not exist where XXX is username for the Linux system where I am mounting the required directories.
While for others I am getting the expected output result.
My concern is "is there any side effect of doing mount and unmount repeatedly in the Linux box?
Or is there any setting in the Linux to make this config to support?
In order to use /bin/su you need to have the user information provided by /etc/passwd. Have you mounted that directory or (as I would recommend) copied it to the /etc/ in the new root directory?
Concerning your mount issues, yes, mounting and unmounting can take some time and is not guaranteed to be instantaneous (especially the unmounting can plainly fail if something is still active on the mounted file system). So maybe you should check if the unmount failed and retry in that case.
Thanks for the reply...Yes you are absolutely right Alfe! it is the problem of mounting/unmounting in a row. I have checked this by SSH login to my web server. when I executed 20-30 program commands repeatedly(separated by semicolon) then I got the desired output in a sequence on my window . then I opened another SSH window and again I executed 10 commands from that window and 20 commands from previous window . when I saw the output then for some commands in both the windows I got that message of "/bin/bash user XXX doesnt exist". so one conclusion is that when I make web requests concurrently then execution of commands(chroot/unchroot) are not in a sync. that's why I am getting this message. I am not very good in Linux . I don't know How can I address this issue.
I have a backup script that runs in the background daily on my linux (Fedora 9) computer. If the computer is shut down while the backup is in progress the backup may be damaged so I would like to write a small script that temporarily disables the ability of the user to reboot or shut the computer down.
It is not necessary that the script is uncirumventable, it's just to let the users of the system know that the backup is in progress and they shouldn't shut down. I've seen the Inhibit method on the DBus Free desktop power management spec:
http://people.freedesktop.org/~hughsient/temp/power-management-spec-0.3.html
but that only prevents shutdowns if the system is idle not explicitly at the users request.
Is there an easy way to do this in C/Python/Perl or bash?
Update: To clarify the question above, it's a machine with multiple users, but who use it sequentially via the plugged in keyboard/mouse. I'm not looking for a system that would stop me "hacking" around it as root. But a script that would remind me (or another user) that the backup is still running when I choose shut down from the Gnome/GDM menus
Another get-you-started solution: During shutdown, the system runs the scripts in /etc/init.d/ (or really, a script in /etc/rc.*/, but you get the idea.) You could create a script in that directory that checks the status of your backup, and delays shuts down until the backup completes. Or better yet, it gracefully interrupts your backup.
The super-user could workaround this script (with /sbin/halt for example,) but you can not prevent the super-user for doing anything if their mind is really set into doing it.
There is molly-guard to prevent accidental shutdows, reboots etc. until all required conditions are met -- conditions can be self-defined.
As already suggested you can as well perform backup operations as part of the shutdown process. See for example this page.
If users are going to be shutting down via GNOME/KDE, just inhibit them from doing so.
http://live.gnome.org/GnomePowerManager/FAQ#head-1cf52551bcec3107d7bae8c332fd292ec2261760
I can't help but feel that you're not grokking the Unix metaphor, and what you're asking for is a kludge.
If a user running as root, there's nothing root can do to stop root from shutting down the system! You can do window dressing things like obscuring shutdown UI, but that's not really accomplishing anything.
I can't tell if you're talking about this in the context of a multi-user machine, or a machine being used as a "desktop PC" with a single user sitting at a console. If it's the former, your users really shouldn't be accessing the machine with credentials that can shutdown the system for day-to-day activities. If it's the latter, I'd recommend educating the users to either (a) check that the script is running, or (b) use a particular shutdown script that you designate that checks for the script's process and refuses to shutdown until it's gone.
More a get-you-started than a complete solution, you could alias the shutdown command away, and then use a script like
#!/bin/sh
ps -ef|grep backupprocess|grep -v grep > /dev/null
if [ "$?" -eq 0 ]; then
echo Backup in progress: aborted shutdown
exit 0
else
echo Backup not in progress: shutting down
shutdown-alias -h now
fi
saved in the user's path as shutdown. I expect there would be some variation dependant on how your users invoke shutdown (Window manager icons/command line) and perhaps for different distros too.
But a script that would remind me (or another user) that the backup is still running when I choose shut down from the Gnome/GDM menus
One may use polkit to completely block shutdown/restart - but I failed to find method that would provide a clear response why it is blocked.
Adding the following lines as /etc/polkit-1/localauthority/50-local.d/restrict-login-powermgmt.pkla works:
[Disable lightdm PowerMgmt]
Identity=unix-user:*
Action=org.freedesktop.login1.reboot;org.freedesktop.login1.reboot-multiple-sessions;org.freedesktop.login1.power-off;org.freedesktop.login1.power-off-multiple-sessions;org.freedesktop.login1.suspend;org.freedesktop.login1.suspend-multiple-sessions;org.freedesktop.login1.hibernate;org.freedesktop.login1.hibernate-multiple-sessions
ResultAny=no
ResultInactive=no
ResultActive=no
You still see a confirmation dialog but there are not buttons to confirm. Looks ugly, but works ;)
Unfortunately this applies to all users, not only the lightdm session, so you have to add a second rule to white-list them if desired.
Note that this method block solely reboot/etc commands issued from GUI. To block reboot/etc commands from command line one may use molly-guard - as explained in https://askubuntu.com/questions/17187/disabling-shutdown-command-for-all-users-even-root-consequences/17255#17255