General :: Processes With Effective User Name Or ID
May 21, 2009
I am studying for the LPIC-1 exam, and reading a book that they recommend: "Introduction to Linux: A Hands-on Guide", by Machtelt Garrels. There's one question on the 4th chapter (Processes), that I found confusing: Question: Based on process entries in /proc, owned by your UID, how would you work to find out which processes these actually represent?
What does he mean? If I run the command (considering that my username is sl33p):
Code:
$ps -u sl33p
...gives me the right answer?
The ps man page says:
-u userlist
Select by effective user ID (EUID) or name.
This selects the processes whose effective user name or ID is in userlist. The effective user ID describes the user whose file access permissions are used by the process (see geteuid(2)). Identical to U and --user.
user@host$ killall -9 -u user Will it definitely kill all processes owned by user (including forkbombs)?
No new processes is spawned to user from other users. No user's processes are in D-sleep and unkillable.No processes are trying to detect and ptrace or terminate this started killall (but they can ptrace or do other things with each other) There is ulimit that prevents too much processes (but killall is already started and allocated it's memory)
E.g. if killall will finish untampered and successfully is it 100% that no processes are left with this uid? If no, how to do it properly (with standard commands and no root access). Will SysRq+I definitely kill all things (even replicating)?
All the kill idle user processes scripts I've seen don't take into account that the user might have multiple sessions open. Such is the case with one of our clients. Currently, every hour or two I need to do the following:
This will get the TTY and idle time for all users.
For each idle time over a half hour, I do the following (TTY is the TTY from the previous command with a space.
I then kill those processes.
There must be a way to do this automatically in a bash or perl script. I've tried both, but can't seem to get things to work properly.
I would like to give a non-root user (nicollet) the ability to detect and send a signal to processes started by Apache2 (those processes are FastCGI scripts and the signal tells them to empty their cache). The processes are owned by the web user (www-data), and I'm running on Debian unstable.
I can't find any way to have the nicollet user see those processes.
The processes are running and can see by both root and www-data:
The most surprising is that the grep process is indeed run by www-data (because it's started from a setuid executable) and is visible, but the baryton process isn't.
What's going on here? Why can ps run by www-data show those processes, but ps run by a setuid executable running as www-data cannot, when it's started by nicollet?
Few days ago, the server did not respond to a ssh request from a user at night. A user tried to check what went wrong with computer and tried to login from terminal next morning. As the computer was unresponsive, he somehow decided to boot it by turning the power off. To make the story short, the server rebooted; however, he can't login to his account. Actually, the server could not start some processes; but was able to ask user to enter his account username. Even though, he enters the correct username and password, server does not accept the request. I also could not login as root.
I just checked the server logs by booting it in single user mode. Here are some interesting lines:
Before the reboot:
irqbalance : can't balance irqs on a uniprocessor system: failed
After the reboot:
irqbalance : can't balance irqs on a uniprocessor system: failed fsck: fsck /: (this is repeated 900+ times)
Normally all I/O goes through the kernel so that it can schedule the operations and prevent processes from stepping on each other. A few special user processes are allowed to slide around the kernel, usually by being given direct access to I/O ports. X servers are the most common example of this isn't it ? give examples for any other processes that are allowed to slide around the kernel ?
I'm trying to get the end result to have the same format as this as well:
1 bin 2 daemon 67 erozner
[code]....
Where the numbers are the number of processes being run by the user (the name right next to it).if I input the command egrep myFile into the terminal, it should look for every line with the letter x in myFile, right?
I have some domains on a VPS server. Typical account memory usage for all domains runs at 50% of available, but I have a problem. One domain is causing me trouble because intermittently traffic will spike on that domain, causing so many requests within 1 min that I exceed my memory allocation for my entire VPS package. Apache is then killed but the virtualization software and Apache must then be restarted.
A sample snippet from tops right before the sever went down would like like this:
All of that memory usage adds up. I would like to "throttle" the number of processes that user/domain can run. I think this would be a quick and easy way to keep the domain from taking down my entire VPS. My understanding is that I could do this with the /etc/security/limits.conf file.
Is that correct?
I have never done this before. Do I want to set a hard or soft limit? I think if I wanted to limit the number of processes for "coldclim" to 15 I would add a line to limits.conf like this:
Code:
Assuming that is correct, can anyone tell me how the website would respond once it reached its limit? Would visitor queries become sluggish, or would the website not come up for them at all?
I have a problem with the permission of the directories under /proc, they are readable and accessible only by Owner (they have permission 500 instead of the usual 555) As a consequence, the processes are visible only to the Owners or to Root. For exampleif I want to check if there is mysql
I see it only with the user mysql or with root because the directory has permission 500
This problem obstacles the functioning of some applications that should check the existence of some processes managed by other users. At the beginning all was working well. But after a while the problem appeared and I dont know which is the reason of it. how to restore the standard management of permissions of / proc?]
I have two NASes. I work off of one, and the other is used as a backup. As I have it set up now, it's slow. Running a backup takes a week. Even for 7 TB, with 1,979,407 files, this seems a bit outlandish,particularly as both systems are RAID-5 and the network is all gigabit. I've been digging about in the rsync man pages, and I really don't understand what differentiates the various topologies.Right now, all the processing is being done on the backup NAS, which has the main volume from the main NAS mounted locally over SMB. I suspect that the SMB overhead is killing me, particularly when dealing with lots of files.
I think what I need is to set up rsync on the main nas as a daemon, and then run a local rsync client to connect to it, which would hopefully allow me to completely avoid the whole SMB-in-the-middle affair, but aside from mentioning that it's there, I can find very little information on why one would want to use the daemon mode for rsync.
Here's my current rsync command line: rsync -r -progress --delete /cifs/Thecus/ /mnt/Storage/input? Is there a better way/tool to do this? Edit:Ok, to address the additional questions: The "Main" NAS is a Thecus N7700. I have additional modules installed that give me SSH, and it has rsync, but it's not in the $PATH, and I havn't figured out how to edit the local $PATH in a way that persists between reboots. The "Backup" NAS is a DIY affair, built around a 1.6Ghz Via Mobo with a Adaptec Hardware RAID card. It's running CentOS 5 with a full desktop environment. It's the hardware I'm running rsync from. (Gigabit is through a additional PCI card).
Further Edit: Ok, got rsync over SSH working (thanks, lajuette!).I had to do a bit of tweaking on my command line, I'm running rsync with the args:rsync -rum --inplace --progress --delete --rsync-path=/opt/bin/rsync sys@10.1.1.10:/raid/data/Storage /mnt/Storage (Note: I'm specifically not using -a, because I want to change the ownership to the local account, to not freak-out SELinux)
Just a few words in the form of introduction.I have just purchased an older server to use on my home LAN.I understand that the use of Linux or Unix as an operating system will be effective in detering the gathering of viruses from the internet.I am totally unfamiliar with either system, but if this is the case, that's about to change.
is there any possible way to hide currently running processes from an user? This means I do not want him to know about what programs/processes does any other user but him run. In short words if that user runs 'ps -aux' he should get only his processes.
Few days ago, the server did not respond to a ssh request from a user at night. A user tried to check what went wrong with computer and tried to login from terminal next morning. As the computer was unresponsive, he somehow decided to boot it by turning the power off. To make the story short, the server rebooted; however, he can't login to his account. Actually, the server could not start some processes; but was able to ask user to enter his account username. Even though, he enters the correct username and password, server does not accept the request. I also could not login as root.
I just checked the server logs by booting it in single user mode. Here are some interesting lines:
Before the reboot: irqbalance : can't balance irqs on a uniprocessor system: failed
After the reboot: irqbalance : can't balance irqs on a uniprocessor system: failed
this is scary, bunch of vmware-user-wra processes stall cpu 100%!! What's going on? Server has just been restarted! Bere I restarted, the root started all this vmware-user-wra!! I was configuring vncserver! After restart, it's started by user roo300 which I have used to login via SecureShell!
I have what I think is a somewhat different failure of standby than I've seen listed on other threads, and I'm stumped.The system hangs on this for a while, then comes back to the login screen without going into standby. This ONLY HAPPENS on a SECOND standby attempt--the first standby after booting ALWAYS succeeds.The standby log doesn't indicate any failures.I had made other changes previously that temporarily got standby working consistently:/etc/default/grub: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.autosuspend=-1"
the problem i have is that when i enter my username, the output (my real name) does not display in the output.txt. instead it displays in putty. so when i run my script in putty it shows the message to enter username and after i enter my username my real name appears below it. i want it to show in the output.txt
ever since i installed Lucid, firefox's pop-up blocker has been much less effective, I'm getting four or five pop ups per session, and i have never put any exceptions into firefox's settings under the pop up blocker. any reason this should be happening?
I was searching on google for syncing my iphone 3gs in linux. I have seen many forums which say that Rhythmbox and gtkpod are able to sync iphone but I did not find any of them to be very helpful in my case. Any Way syncing iphone in linux so that I don't have to boot to windows.
I've been reading about getopt and getopts but it doesn't seem like it's possible to parse arguments like --foo or even -foo. I've started my own script trying to achieve this, but I'm still wondering if I'm losing performance and if there is a better way to do this task.
Also I'm using the [[ =~ ]] regex syntax which seems to be available only in newer bash versions, should it be a big issue? My bash version: GNU bash, version 4.1.7(2)-release (x86_64-unknown-linux-gnu)
I just installed Ubuntu on my laptop (x200s, XPpro with 230 Gb), and created a 30Gb partition therefore. At the end of the install, the screen remained orange for a while, without any disk activity. I forced the laptot to reboot, but Ubntu was no option when the machine restarted. However, my XP partition has been reduced by 30 Gb. Does anybody have an idea about what I should do to either get Ubuntu installed or recover the disk space?
Created application is working too slow, looks like there are a lot of memory leaks, there are a lot of pointers. Any effective tool for run-time errors and memory leaks detection in Visual Studio C++?
I had this error when installing and running a vncserver before, which I have now removed. However, the xterm's seem to remain in the system and are regenerating themselves. Should the pid IDs stay the same each time I run this?
I need to create a small list of processes in a monitor.conf file. A shell script needs to check the status of these processes and restart if they are down. This shell script needs to be run every couple of minutes.
The output of the shell script needs to be recorded in a log file.
So far I have created a blank monitor.conf file. I have gotten the shell script to automatically updated every couple of minutes The Shell script also sends some default test information to the log file.
how I go about doing this part ? A shell script needs to check the status of these processes and restart if they are down.
I have put in the conf file the below commands but I am not sure if this is right.
ps ax | grep httpd ps ax | grep apache
I also dont know if the shell script should read from the conf file or if the conf file should send information to the shell script file.
