Questions tagged [linux]
Linux is the generic term for a UNIX-like open source operating system based on the Linux kernel.
7,539
questions with no upvoted or accepted answers
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Is it possible to do multiseat the systemd way with one graphic card / two heads?
I would like to setup a multi-seat configuration using Ubuntu Xenial 16.04.
After some researches, it seems the way to do now is by systemd through "loginctl" calls. (saw here for example).
Before ...
10
votes
0
answers
2k
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CentOS 6 local update repository and security updates
I know that official CentOS 6 (even 7) update repositories does not provide security information. The consequence is thatyum-plugin-security plugin and yum check-update --security command does not ...
8
votes
1
answer
344
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Can Samhain monitor for a file that does not exist, but might in future?
I would like Samhain to monitor a file, say for example, /root/somefile. This file does not currently exist, but I would like to be notified if it gets created at any point.
I add this to samhainrc:
...
8
votes
2
answers
1k
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what is the IOPS behavior when partitions of single disk are used in an LVM?
I have an ubuntu 14.04.1 LTS server which have LVM(backed by hardware RAID5) with logical volume and a volume group named "dbstore-lv" and "dbstore-vg" which have sdb1 sdb2 sdb3 created from same sdb ...
8
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0
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ZFS cannot import : I/O error
I experienced an error in my ZFS machine. This may have happend after I lost power to my server, but I can not tell for sure. My ZFS Pool Gewuerzglas with RAIDZ-1 is no longer willing to import. I ...
8
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0
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how to tune NFS client on MacOS to get Linux like performance?
I have a NFS server running Linux and exporting a couple of shares. Both Linux and MacOS clients connect to the server, and while with the Linux clients I get ~ 75MB/s write speed, the MacOS clients ...
7
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Applying systemd control group resource limits automatically to specific user applications in a gnome-shell session
Having seen that GNOME now launches apps under systemd scopes I've been looking at a way to get systemd to apply some cgroup resource and memory limits to my browser.
I want to apply a MemoryMax and ...
7
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2
answers
1k
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What repository is a yum group sourced from?
Is there an easy way to determine where a specific yum group is sourced?
I can query what groups are available using yum grouplist.
I can query group information using yum group info $yum_group_name
...
7
votes
0
answers
2k
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TCP congestion collapse
I am experiencing suboptimal performance on an EC2 instance connecting to an RDS instance. This particular instance was built before VPC's existed, so all the traffic is flowing through a single ...
7
votes
5
answers
6k
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Creating a fallback error page for nginx when root directory does not exist
I have set up an any-domain config on my nginx server - to reduce the amount of work needed when I open a new site/domain. This config allows me to simply create a folder in /usr/share/nginx/sites/ ...
7
votes
1
answer
857
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Intermittent munin-cron error “There is nothing to do here, since there are no nodes with any plugins”
We've installed munin monitoring on one of our servers. Generally it seems to be working well but occasionally, 4 times in 2 months to be exact, munin-cron has generated the following error:
[...
6
votes
0
answers
944
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AWS: Can't mount my restored volume (EBS snapshot)
I restored an EBS volume from AWS Backup and attached it to a new EC2 instance. When I lsblk I can see it under the name /dev/nvme1n1.
More specifically the output of lsblk is:
NAME MAJ:MIN RM ...
6
votes
0
answers
2k
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Caching, forwarding Bind 9.9.4 server works for weeks, suddenly SERVFAIL on all queries (rebooting fixes it)
I have bind 9.9.5 running on two servers (CentOS 6 and 7), for caching and forwarding DNS queries for a mail server. The servers run fine for weeks, then suddenly respond to all queries with SERVFAIL. ...
6
votes
1
answer
1k
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nano very slow over ssh
Recently nano has started to be very slow when editing files over ssh. It's particularly slow when editing large files with syntax highlighting.
It's most noticeable when yanking lines. There can ...
6
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0
answers
163
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Write arbitrary attribute into ENV from LDAP upon successful PAM authentication
Is it possible during the authentication phase of pam_ldap to map an arbitrary LDAP attribute of the user's record into the resulting user's environment?
The specifics of my situation, in case you ...
6
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0
answers
7k
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Server went offline for no reason except SIGINT?
We had a system go offline this morning. The only thing in syslog is:
Mar 20 15:27:15 fooserver systemd[1]: Received SIGINT.
Mar 20 15:27:15 fooserver systemd[1]: Starting Synchronise Hardware Clock ...
6
votes
1
answer
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How do I secure the access token, on Linux, to remote, automated secrets stores like Hashicorp Vault?
There seems to be a bit of a "chicken and egg" problem with the passwords to the password managers like Hashicorp Vault for Linux.
While researching this for some Linux servers, someone clever asked, ...
6
votes
1
answer
2k
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Inconsistent winbind info on Samba 4 AD domain controller
I've setup a Samba 4 AD domain controller on Debian Jessie (samba 4.2.10). Everything's working fine, except that winbind gives wrong user/group information.
I have a sample user "testuser" and a ...
6
votes
2
answers
992
views
Q: RHEL, SSSD, Active Directory
Good afternoon folks. I've been perusing various posts already about getting linux systems to authenticate using AD, but haven't seen anything approaching what I'm beating my head against.
There's a ...
6
votes
1
answer
209
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Can servers with encrypted root filesystems be made reasonably highly available?
I have some servers I'd like to keep on encrypted disks, but I don't want to have to manually type a passphrase at every boot. I also don't want to keep the key on the machine unencrypted. TPM would ...
6
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0
answers
6k
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Wrong filename encoding/decoding when downloading recursively with wget
I'm downloading files from a remote directory recursively using wget and whoever created the folders and files, used special characters such as è or Ó, when I download a single specificating the full ...
6
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0
answers
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How can I let rsync display both total and partial progress?
I've found that rsync's total progress is (somewhat) shown with --info=progress2, while partial progress (i.e. the current file) is shown with --info=progress (or -P).
Is there a way to show both?
I'...
6
votes
1
answer
2k
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SSSD process won't die
Thanks for taking the time to check out my problem.
I'm currently working on an issue that has only appeared once before. Back on Jan 3rd when this first appeared we were able to reboot the server ...
6
votes
2
answers
2k
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Not Able to Mount USB HDD in Linux
I'm having a problem with a server that I just installed kernel 2.6.18-371.el5 on. It's an old kernel for Red Hat 5, I know, but due to certain "restrictions" I am forced into using that for the time ...
6
votes
1
answer
18k
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Tons of "invalid command \N" when restoring a dump
I'm following these instructions to upgrade postgres from 9.1 to 9.3:
http://www.postgresql.org/docs/9.1/static/upgrading.html
When I restore (Step 8), I get a ton of messages like this:
psql:/mnt/...
6
votes
0
answers
21k
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ActiveMQ - "Cannot send, channel has already failed" every 2 seconds?
ActiveMQ 5.7.0
CentOS release 6.3
java version "1.6.0_26"
Application server: Tomcat
In the activemq.log, I'm seeing this exception every 2 seconds:
2013-11-05 13:00:52,374 | DEBUG | Transport ...
6
votes
1
answer
4k
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Linux Client Active Directory Authentication stops working when failover
I have an issue with Linux clients trying to AD authentication by targeting a DNS name (corp.example.com). I have 2 Domain Controller servers DC1(10.0.0.3/24), DC2(10.1.0.3/24) both domain controllers ...
6
votes
1
answer
5k
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How to mount vfat drive on Linux with ownership other than root?
I'm running into trouble mounting an iPod on a newly upgraded Debian Squeeze.
I suspect either a protocol has changed or I've tickled a bug, which I don't know where to report.
I'm trying to mount the ...
5
votes
0
answers
262
views
firewall-cmd to drop existing connections
I want to use firewall-cmd to temporarily block mysql port 3306, including existing connections.
However after I remove MySQL service, only new connections are blocked. The existing connections are ...
5
votes
2
answers
4k
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100% CPU usage reported, but no processes using the CPU
I am running Debian 10 (kernel 4.19.0-18-amd64) on bare metal and I have recently noticed strange CPU usage.
Screenshot of htop, sorted by CPU%
Screenshot of top, sorted by CPU%
As you can see, 100% ...
5
votes
0
answers
12k
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Mount filesystem with "structure needs cleaning" on ext4
There is a created years ago(and many time resized from that times) filesystem with ext4. After power failure it stop to mount.
When i try to mount it manually i receive an error:
# mount /dev/space/...
5
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0
answers
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Interpreting resize2fs shrink progress (-p) "pass 2" output
The question: What is resize2fs's progress bar indicating during "pass 2" of an offline shrink operation on a large (8-28Tb) ext4 filesystem?
The details:
I've done ~5 resize2fs shrink ...
5
votes
1
answer
5k
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RSYSLOG not creating tcp port
At a certain point this was working and I do not know what could have changed. No logs are going to the TFTP folder and instead I just see the error message posted below. I tried rebooting the server. ...
5
votes
0
answers
2k
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Samba and AD - "net ads changetrustpw" fails
I've got a Samba member of a Windows AD. I'm using a combination of sssd and winbind. Samba manages machine password changes, and it's configured also to update the passwords used by sssd. (The ...
5
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0
answers
671
views
How to dump the kernel stack trace of a failed system call?
This is a canonical question. I want to understand why a specific system call is failing. Is it possible to display the kernel stack trace of the syscall:
when the return is non-zero or is negative (...
5
votes
1
answer
5k
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systemd-journal Rate Limit
I have a service set up on CentOS 7 which outputs a lot of log messages, which results in this in the system log / journal: systemd-journal[xxxx]: Suppressed 864 messages from /system.slice/example....
5
votes
1
answer
2k
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How long is an (accepted) ICMP redirect observed for, and how can I shorten that time?
If a Linux host receives and accepts an ICMP redirect (accept_redirects=1 on the interface in question), how long is this route being cached for and observed? Can I lower that time?
I am asking ...
5
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0
answers
3k
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Clarification regarding Deep Packet Inspection in the Linux Kernel's Netfilter section
The Linux Kernel provides Netfilter as a mechanism for both NAT and firewall functionality. Both of those functionalities require analysis and classification of incoming packets, which is dubbed "...
5
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0
answers
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Use of cores with `isolcpus` and `cpuset`
I have a Red Hat Enterprise Linux Server release 6.9 (Santiago) (I don't manage it). In the GRUB config file I have, let's say, isolcpus=2-32 (out of 36 cores). I also have a cgroup with cpuset=2-32 ...
5
votes
1
answer
2k
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How to debug failed checksums/flipped bits in TCP packets?
A web application we maintain recently encountered a very weird problem: three out of four virtual machines on two physical hosts had trouble connecting to the server of our payment provider via HTTPS....
5
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0
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Auditd in a PCI-DSS-compliant Linux cluster
I'm familiar with some of the more common ways of configuring a Linux server to be compliant with PCI-DSS 3.2, at least to the requirements of SAQ A. A common concern is requirement 8.5 which ...
5
votes
2
answers
6k
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Linux SMB to \\domainname ends up "tree connect failed: NT_STATUS_DUPLICATE_NAME "
Issue:
From CentOS7 machine:
smbclient -L %domainname%.com --user=%username%
Result:
tree connect failed: NT_STATUS_DUPLICATE_NAME
This is especially when I try to connect to //domainname.com, ...
5
votes
3
answers
5k
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avoiding repetition in supervisord config for multiple programs
I have to run multiple instances of same app with slightly different settings. Only thing that changes is one command line parameter.
So currently I've got script which looks something like this:
[...
5
votes
0
answers
649
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Send linux kernel paramters to VM guest in VMware
I have research a lot about this but I can't find anything that answers my question.
My question is how would I send/pass linux kernel parameters to a VM guest in VMware vsphere (so I don't need to ...
5
votes
1
answer
1k
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Can't communicate between multiple interfaces on same subnet
I have multiple ethernet interfaces on one machine, all on the same subnet. Normally these are set up to run on separate VM's, and I understand the limitations imposed by Linux as described here, but ...
5
votes
1
answer
2k
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difference between ifdown, ifconfig stop and ONBOOT=no
my ifcfg-eth1 config as below
DEVICE=eth1
TYPE=Ethernet
UUID=5e4f36f8-14eb-4f0c-8fa9-3af9be3899a7
ONBOOT=no
NM_CONTROLLED=yes
BOOTPROTO=dhcp
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
NAME="...
5
votes
2
answers
582
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timing issue after route add/delete (route not used)
I have an application that is running a raw IP socket, destination of this socket is governed by routes installed via the 'ip route add' command. These routes can change during the lifetime of a ...
5
votes
0
answers
2k
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TCP connections in FIN-WAIT-2 state on linux not timing out according to tcp_fin_timeout
We run a service with lots of embedded devices in the field, their tcp stack is a bit buggy and sometimes does not close connections properly, resulting in some connections being stuck in FIN-WAIT-2 ...
5
votes
1
answer
2k
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keepalived config is not working correctly with virtualbox vms
my keepalived configuration is not working correctly.
I have two virtual testing machines (virtualbox) to try some things out with keepalived/vrrp. Bot can ping each other flawlessly (internal ...
5
votes
0
answers
4k
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NAT64 configuration with tayga on Debian 6
I'm trying to implement NAT64 with tayga on my server and came to a point where I'm not sure how to proceed.
My server is connected via one IPv4 address and one /64 IPv6 address block to the internet....