An apache2 process got stuck on my server and caused problems with other services. (original problem: kerneloops after USB hardware disconnect)   root@server:~# ps aux | grep apache2 | grep -v grep www-data 12917  0.0  0.1 412148 16156 ?        D    Jun27   0:00 /usr/sbin/apache2 -k start   Naturally, I killd it. it's still alive. so I kill -9d it. It's still "alive".  Now this is where the question gets serverfault/unix&amp;linux-worthy: Is there a way to get port 443 back without doing the obvious thing: rebooting? Iptables is installed.  Update: I could not resolve the Problem withouth rebooting. The general approach (use lsof or /proc/$PID/fd to find out which and get rid of that drive) as described here and in the "duplicate" could well have worked if not for additional (probably) hardware defects.
2490
I have a process I can't kill with kill -9 &lt;pid&gt;. What's the problem in such a case, especially since I am the owner of that process. I thought nothing could evade that kill option.
59079
Here is what I have got:   CentOS 5.4 (32-bit)    installed Apache httpd (Server version: Apache/2.2.11 (Unix)) mod_rewrite already presents   Question: how to redirect simple  to  not using VirtualHost defines?  PS: tried to find in later answers on SF, but doesn't find nice solution.  Thanks.
82365
A colleague once told me that the last option when everything has failed to debug on Linux was to use .  I tried to learn the science behind this strange tool, but I am not a system admin guru and I didn’t really get results.  So,   What is it exactly and what does it do? How and in which cases should it be used? How should the output be understood and processed?   In brief, in simple words, how does this stuff work?
10988
How do I stop Apache2 from automatically starting on boot? I can't seem to find an option that disables the automatic start-up when I turn on the machine.
117347
I am working on an apache2 reverse proxy vhost. When the server behind apache is down, the first request to apache shows the error page of course.   But at subsequent requests it seems apache delays for some time before asking the backend server again. During all this time (which is short but in development I don't want a delay at all) only the apache error page is shown to the browser, although the backend server is already up.  Where is this setting in apache, what is this behaviour, and how can I set the delay time to zero?  Edit: I am not trying to change the timeout for a single request. I want to change the blocking time. It is my experience that apache blocks further requests for a certain time before asking a backend server again that has failed once.   Edit2: This is what apache delivers:  Service Temporarily Unavailable  The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.  Apache/2.2.8 (Ubuntu) PHP/5.2.4-2ubuntu5.7 with Suhosin-Patch proxy_html/3.0.0 Server at localhost Port 80  After hitting Ctrl-R in firefox for 60 seconds the page finally appears.
111208
I've just started using Debian 8 which has introduced systemd. I'm not interested in the politics around SysV vs systemd, but I am confused, especially around Apache (2.4).  There are now two ways to restart apache:   apache2ctl restart or apache2ctl graceful systemctl restart apache2 and it seems systemctl restart apache2.service does the same thing.   And they appear to do different things(!). I don't understand the difference.  I seem to need to do both to get a proper full restart working. e.g. after changing a config file for the php module it only noted the change after both.  Another time when apache2ctl configtest was failing and the failure was reported in systemctl status apache2 I fixed the config so that the first of these commands was happy, restarted with apache2ctl restart but the systemd status command still listed it as not running and with the old config problem.  I promise to spend ages reading about systemd (RTFM) in depth at some point, but meanwhile on a practical level relating to apache, I'd appreciate advice.
35897
What's the best approach towards determining if I have a rogue DHCP server inside my network?  I'm wondering how most admins approach these kinds of problems.  I found  through searching, and thought about trying it out.  Has anyone had experience with it? (I would like to know before taking the time to compile it and install).  Do you know any useful tools or best-practices towards finding rogue DHCP servers?
24887
NFS mounts recently automatically got un-mounted. When I checked, the NFS service status it was shown to be running.  [root@hsluasrepo]# service nfs status rpc.svcgssd is stopped rpc.mountd (pid 4083) is running... nfsd (pid 4148 4147 4146 4145 4144 4143 4142 4141) is running... rpc.rquotad (pid 4079) is running...  [root@hsluasrepo]# service rpcbind status rpcbind (pid  4203) is running...  [root@hsluasrepo common]# rpcinfo -p 10.80.3.154    program vers proto   port  service     100000    4   tcp    111  portmapper     100000    3   tcp    111  portmapper     100000    2   tcp    111  portmapper     100000    4   udp    111  portmapper     100000    3   udp    111  portmapper     100000    2   udp    111  portmapper   But showmount output was showing an error.  [root@hsluasrepo ]# showmount -e 10.80.3.154 clnt_create: RPC: Program not registered   After restarting the NFS service, showmount output displayed the NFS server's export list.  Can anyone tell me the root cause of this issue and How to avoid this problem in future?  /var/log/messages:  Jul 7 03:22:01 hsluasrepo rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1188" x-info="rsyslog.com"] rsyslogd was HUPed Jul 7 03:22:02 hsluasrepo rhsmd: In order for Subscription Manager to provide your system with updates, your system must be registered with RHN. Please enter your Red Hat login to ensure your system is up-to-date. Jul 8 03:22:01 hsluasrepo rhsmd: In order for Subscription Manager to provide your system with updates, your system must be registered with RHN. Please enter your Red Hat login to ensure your system is up-to-date. Jul 8 16:36:55 hsluasrepo kernel: nfsd: last server has exited, flushing export cache Jul 8 16:36:55 hsluasrepo rpc.mountd[4083]: Caught signal 15, un-registering and exiting. Jul 8 16:36:55 hsluasrepo rpc.mountd[24463]: Version 1.2.3 starting Jul 8 16:36:55 hsluasrepo kernel: NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory Jul 8 16:36:55 hsluasrepo kernel: NFSD: starting 90-second grace period Jul 8 16:37:32 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.208:1004 for /common/PROD (/common/PROD) Jul 8 16:38:09 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.181:869 for /common/PROD (/common/PROD)  Jul 8 16:38:43 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.180:825 for /common/PROD (/common/PROD) Jul 8 16:39:12 hsluasrepo rpc.mountd[24463]: authenticated mount request from 10.60.5.176:688 for /common/PROD (/common/PROD)
92951
I've tried to open port 8605 on my server (used for socket connections) using:  iptables -I INPUT 2 -s 0/0 -p tcp --dport 8605 -j ACCEPT   However the change is not persisting, the port closes itself once a day (I assume something is being regularly reloaded).  How can I make my change persist?  EDIT  Despite saving it, the change does not persist, each day it needs to be corrected.  Crontab does not seem to have any obvious changes, and the server is not restarting. Any ideas?  EDIT  I found out that iptables was running under  so I needed to updated the rules in there.
92453
What is the Linux command to check the server OS and its version?  I am connected to the server using shell.
55913
So I've got a persistent program running in the background. Killing it just causes it to restart with a different PID. I'd like to suspend it (put it to sleep without actually killing it). Does kill -9 do this? If not, how should this be done?
33043
I am using Ubuntu 14.04.  I ran in terminal sudo apt-get update. Then I rebooted the system. And now I see:   ALERT! /dev/disk/by-uuid/xxxxxxxxx does not exist. Dropping to a shell initramfs:_   I can't boot up LIVE Ubuntu from USB flash drive. Yes, I double checked BIOS setup and the USB flash drive is OK and runs on another machine. Right now I am going to buy a  DVD and burn a Live DVD from another laptop.  sudo blkid gives me:   /dev/loop0: TYPE="squashfs"   /dev/sda1: UUID="xxxx" TYPE="ext4"    /dev/sr0: LABEL="Ubuntu 14.04.1 LTS i386" TYPE="iso960"      /etc/fstab has the same UUID="xxxx" and there is a line with:   errors=remount-ro 0      I tried using boot-repair but I still can't log in to Ubuntu.  I don't want to reinstall Ubuntu, because I have a lot of data there.  Do you have any advice how this can be solved?
85849
The drive is constantly filling up. You've hunted down all the spare and random files you can. grep'd for coredump files and even removed some of the un-needed backups...  What would be your next move.  The actual server in question has 10GB of website files and the OS shouldn't take any more than 10GB so how do you track down what's filling a 50GB (virtual) drive?
19914
How do I kill all processes running by my own non-root account?  I have some spinning smbd  processes that I caused from my windows machine and so I telnetted into the linux server and I want to kill those spinning processes.   I don't have authority to restart services or reboot the machine.
59507
I have a Linux server (Ubuntu 12.04) I'm using to learn as much as I can about server management. I've got as far as getting a full LAMP setup running, but have hit a dead end trying to get a domain name to point to my server.  I've set up a virtual host in an Apache .conf file, and set up the IP address in the hosts file with the domain name, and have pointed the A record to the IP address with no luck. I've also installed bind9, but thought I'd see if I'm going in the wrong direction rather than messing anything up with that.  What is the best way to get a domain name up and running - ideally in a way that would be production ready rather than a temporary setup  EDIT: Thanks for the tips - just to better inform the situation - I have a few spare domain names registered that I can use, and I'm renting a VPS to play with. Currently I have the DNS * and @ A record pointing to the IP, but the nameservers are with the registrar if that makes a difference?
63105
I have Ubuntu Server 11.04, but it is headless (no monitor). The only way I want to be able to access it is remotely via SSH. But, sometimes, say after a power loss, when the server restarts, it will get stuck on the Grub boot menu, and it won't count down. It will just hang there waiting for me to choose the first boot entry. This means I have to go there and plug in a monitor and keyboard.  But I can't do that remotely. How can I force it to continue booting to boot entry 1 (default) regardless of power loss or whatever?
113632
I wanted a daemon to start on boot so I added a line to /etc/rc.local that ended in "&amp;"  I did that so it would run in the background.  The daemon is loaded and working fine but when the daemon is running you can press keys that do other important things.  When I am finally logged in I wanted to resume process or send it a terminal (tty2) so I can do a couple of things.  I'm new to linux and not sure how to do this.  I do a ps -aux |grep uox to work out which PID it is. But not sure how to resume.