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How to make NTP work despite a high offset?

Recently I have kickstarted some servers that had their time off by a month in the bios. The time in the bios said it was a random time/date in May, while it was June. This caused NTP not to work, ...
6
votes
2answers
13k views

Account Lockout with pam_tally2 in RHEL6

I am using pam_tally2 to lockout accounts after 3 failed logins per policy, however, the connecting user does not receive the error indicating pam_tally2's action. (Via SSH.) I expect to see on the ...
6
votes
2answers
5k views

“open files” ulimit: controlling via limits.conf

I'm banging my head on this, and I can't understand why it's not working. I'm hoping that someone can shed light on this, or failing that, give me some suggestions for avenues of investigation. I've ...
6
votes
1answer
5k views

Change CUPS default printer error policy

I run CUPS printing on a number of multiuser Linux application servers. The systems are RHEL or CentOS version 4, 5 or 6. Starting the EL5, the CUPS print server defaults to an error policy that ...
6
votes
1answer
621 views

Need help understanding PAM directives

I have the following directives in my /etc/pam.d/sshd file on a RHEL5 box and I'm a bit confused. These directives are there to make LDAP+RADIUS+OTP work. What I'm trying to do is tell pam not to ...
6
votes
2answers
4k views

How to do client side NFS failover in Linux?

I have a CentOS 6.3 client that needs to access NFS storage. There are two NFS servers that serve up the same content stored on a SAN with a clustered filesystem. How do I set up CentOS to failover ...
6
votes
2answers
763 views

Implications of 100% utilization on dm device

We have a RHEL 5.6 server here with 4 active paths to a single LUN. We suspect that it's not able to cram enough IOs down the pipeline to the XIV on the other end: mpath0 (XXXXXXXXXXXXXXX) dm-9 ...
6
votes
2answers
426 views

SSH unresponsive after stopping Tomcat, many ksoftirqd CPU usage

I have a weird issue. Every time I stop Tomcat, SSH becomes very slow, almost totally unresponsive. It takes a minute or even more for SSH to accept any command. When I finally get Tomcat started ...
6
votes
1answer
386 views

How to make a RHEL repo static for a specific release

I have been working with CentOS for quite a while now and i got used to the way the repos are managed. Recently a new proprietary app required the company to get RHEL licences and the repo management ...
6
votes
2answers
985 views

yum-security for CentOS?

Last time I checked I was able to install yum-security in CentOS but since it doesn't use the official redhat mirrors I was unable to get it to actually work. Is there a way to make yum-security work ...
6
votes
3answers
7k views

Running arbitrary program as daemon from init script

I need to install a program as a service in Red Hat. It doesn't background itself, manage its PID file, or manage its own logs. It just runs and prints to STDOUT and STDERR. Using the standard init ...
5
votes
5answers
1k views

Linux - How to manage the password of root?

We have just deployed a couple of Linux server. Each sysadmin will have his own account on the server (i.e.: jsmith), and will connect using SSH with a certificate which will be put into the ...
5
votes
8answers
2k views

What is the equivalent for “service servicename start” that Fedora/RHEL/CentOS uses for Debian/Ubuntu?

What is the equivalent for "service servicename start" that Fedora/RHEL/CentOS uses for Debian/Ubuntu? I've just read on some question here on serverfoault that using /etc/init.d/service is obsolete, ...
5
votes
3answers
11k views

How do I install 'convert' on a linux system?

My application needs to call 'convert' - http://linux.about.com/od/commands/l/blcmdl1_convert.htm But its not present on my redhat system. How / what do I install?
5
votes
7answers
380 views

List of tools you install on your debian/red-hat server [closed]

Here in a list of tools I install after a fresh install (debian most of time): logcheck: to check the log files and generate reports apticron: send me e-mails when packages updates are available ...
5
votes
1answer
628 views

How to check if an IP address is free on a network

I'm gonna setup a Wireless router for a customer. They have subnet 10.253.48.0/24 What can I do to check if the IP 10.253.48.243 is available to set up the router? I'm on out on a local network at my ...
5
votes
3answers
13k views

What is the difference between RHEV and oVirt?

When I read the wikipedia articles about RHEV and oVirt, I can't really figure out why Red Hat have both projects, as they seam to solve the same problem? http://en.wikipedia.org/wiki/RHEV ...
5
votes
4answers
438 views

Production BIND DNS servers - Do you use the package manager or compile the latest stable edition?

I manage several BIND DNS servers (on RHEL/Centos) for authoritative lookups (forward and reverse) as well as dedicated caching-only services. I've always just used the latest stable BIND in the ...
5
votes
2answers
11k views

How to get ldapsearch on Scientific Linux?

How do I get the ldapsearch on Scientific Linux? I am trying to find the ldapsearch client for Scientific Linux but cannot find how to install the client in order to do LDAP queries.
5
votes
3answers
9k views

Adding an existing user to a group with puppet

Is it possible to add an existing user to a group with puppet 2.7.18? We have two modules, each one defines one class : module "user" creates all users, including user foo and user bar. module ...
5
votes
3answers
9k views

How do I export and restore my iptables settings?

I have what appears to be weird and convoluted set of rules which work for me at the moment. Is there a way of "exporting" those and saving them to a file so that they can be restored later on in case ...
5
votes
4answers
5k views

On AWS do I have to open ports in an EC2 instance's firewall as well as security group?

If I change my SSH port from 22 to 23453, I can no longer ssh in. In more detail, I'm using a Red Hat EC2 instance on Amazon Web Services. This is the second change I've on a fresh install (first ...
5
votes
2answers
461 views

CentOS 6 in production

All of my virtual servers are on Centos 5.5. Now I am deploying new one and there is a new OS option: CentOS 6. I like new software, and I prefer to use new versions (but not the edge). So, as far as ...
5
votes
3answers
2k views

RHN/Yum update from Red Hat Enterprise Linux 5.0 to 5.1

I need to update a server from RHEL 5.0 to 5.1 When I use RHN/Yum and do a yum update the 5.0 server gets updated to 5.6 Is there a way to configure RHN/yum to update the server only to RHEL 5.1 ? ...
5
votes
3answers
3k views

Getting NFS clients to retry mount if NFS server down when client boots

I have an NFS server that several clients mount. I am using the following in my /etc/exports on the server: /content *(rw,no_root_squash) and on the clients in my /etc/fstab I have: ...
5
votes
1answer
7k views

What's the difference between /etc/cron.d and /var/spool/cron?

The crontabs on RHEL seem to be duplicated in two places, /etc/cron.d, and /var/spool/cron. I've checked, and neither of these are simlinks to the other, and neither are any of the crons contained in ...
5
votes
2answers
5k views

On Redhat, what does “kernel.suid_dumpable = 1” mean?

I'm running a bash script to copy some log files and then restart a service on a Red Hat box. Every time I execute the script, I get the following on my console: [root@servername ~]# sh ...
5
votes
3answers
2k views

Kickstart: Serve dynamic kickstart images via a CGI or PHP script?

I'd like to Kickstart a couple dozen RHEL6/SL6 servers. However, some of these servers are different and I don't want to create a new ks.cfg file for each class of server. Is there any way I can ...
5
votes
1answer
2k views

How do I migrate from RHEL 5 to CentOS 5?

I've found myself in charge of installing some software on an old server running RHEL 5. Unfortunately, since it's just a development server now, it no longer rates a license. I'd like to continue ...
5
votes
7answers
10k views

Automated configuration of ldap authentication for RHEL5 servers

I use puppet for managing our production servers. Under rhel5 the standard way of enabling ldap is to use the authconfig tool. Which works successfully, but isn't really capable with the puppet way of ...
5
votes
3answers
481 views

Flash on EL6 for accessing VMware vCenter Appliance 5.5

Has anyone succeeded in connecting to a vcenter 5.5 appliance with a RHEL6 workstation? If so, what's the magic incantation and ritual keystrokes? Made the mistake of upgrading to esxi 5.5 without ...
5
votes
2answers
307 views

Are there any issues migrating from RHEL to CentOS?

I want to migrate off of RHEL 6.3 to CentOS-6 to save in licensing costs. We will mainly be running Java/WebLogic 11g on these boxes. Are there any issues that I should be aware of when migrating from ...
5
votes
1answer
995 views

does rsync's delta algorithm work on a samba share?

I have a cron job to use rsync to sync the data on a windows samba share (that i mount using /etc/fstab on boot). My problem is that the transfer seems to take almost as long as the initial transfer ...
5
votes
2answers
234 views

Any repercussions from not using default primary groups for Linux users?

We were thinking of not using the default primary group for our RHEL users. What I mean by default: User: melbin Primary group: melbin We will instead do something like: User: melbin Primary ...
5
votes
3answers
10k views

Mount CIFS share with autofs

I have a system running RHEL 5.5, and I am trying to mount a Windows share on a server using autofs. (Due to the network not being ready upon startup, I do not want to utilize fstab.) I am able to ...
5
votes
2answers
9k views

RHN Satellite / Spacewalk custom channels, best practice?

I'm currently setting up RHN Satellite, and all works well. I'm in the process of creating custom channels, since we have certain software which should be available for all nodes of satellite, e.g. ...
5
votes
2answers
7k views

Configure a DNS server per nic interface (eth0 / eth1)?

How would you configure a DNS Name Server per NIC (eth0 vs eth1) interface on RHEL/Centos 6? E.g. eth0 is on subnet 10.0.0.1/24 eth1 is on subnet 192.168.0.1/24 Any requests sent over ...
5
votes
1answer
2k views

Debugging fstab problems on reboot

After a reboot, some partitions which were mentioned in fstab were not mounted as expected. The format of the line for the partitions which were mounted correctly and those which were not mounted ...
5
votes
2answers
2k views

Linux kernel crash dump analysis: Guidelines

Note: 2.6+ Kernel Or older 2.4 Question: Generic suggested guidelines with regards to Linux kernel crash dump analysis Skills required, i.e. Kernel compilation skills etc Suggestions: ...
5
votes
5answers
31k views

How can I resize a LVM partition in Red Hat without lose of data?

My partition detail is like this /dev/mapper/VolGroup00-LogVol00 57G 8.8G 46G 17% / /dev/mapper/VolGroup00-LogVol05 259G 7.0G 239G 3% /home ...
5
votes
1answer
173 views

Odd TCP termination sequence

While troubleshooting another thing, I've noticed an odd pattern of TCP closes. Packets: http://www.cloudshark.org/captures/7590ec4e6bef What's happening is that the last few packets of the close ...
5
votes
2answers
492 views

Collecting and centralizing information from many servers, sort of like Puppet's facter

We manage hundreds of RedHat Enterprise Linux servers happily with Puppet. One of the cool side effects is that we can go to /var/lib/puppet/yaml/facts and look at the output of the "facter" utility ...
5
votes
2answers
1k views

RHEL Clones (Centos, Scientific, CERN) network installation on XenServer 6.2

I'm trying to install a Scientific Linux CERN 6 guest on XenServer 6.2 through the network with PXE Booting but it hangs in the message: mounting /tmp as tmpfs... done I'm not using the most ...
5
votes
4answers
3k views

switchless Infiniband between two servers on RHEL 6.3

I have 2 servers running RHEL 6.3 which have 2 port Infiniband cards >lspci | grep -i infini 07:00.0 InfiniBand: QLogic Corp. IBA7322 QDR InfiniBand HCA (rev 02) I'm interested in connecting ...
5
votes
4answers
3k views

Is there a way to prevent password expiration when user has no password?

Okay, we all care about security so users should change their passwords on a regular basis (who said passwords are like underwear?). On redhat and centos (5.x and 6.x), it's possible to make every ...
5
votes
1answer
2k views

Creating a local rpmforge/repoforge mirror?

I make good use of RPMforge for my production CentOS systems. I have local repositories for the main CentOS distribution and updates, however, recent automated kickstart installs are starting to hang ...
5
votes
2answers
2k views

LVM: resize2fs not resizing

I'm having a weird issue with resize2fs. I've performed all the commands and they all have been successful, however, my filesystem is the same size as it was before: [oracle@server~]$ df -h /backup ...
5
votes
2answers
2k views

sudo chown - prevent ../

Need to allow a user to chown files under a particular directory using sudo. This does the trick: user1 ALL= NOPASSWD: /bin/chown -[RPfchv] user2\:user2 /opt/some/path/[a-zA-Z0-9]* But, does not ...
5
votes
3answers
9k views

second ip address on the same interface but on a different subnet

Is it possible in CentOS 5.7 64bit to have a second IP address on one interface (eg. eth0) - alias interface configuration - in a different subnet? Here is the original config for eth0 more ...
5
votes
1answer
21k views

Cannot find open shared object file libjli.so — no such file or directory

On 64-bit RHEL5 running Java 1.6.0 update 16, root can successfully run a Java program but a user can't because libjli.so supposedly can't be found. SELinux is turned off and the environment is the ...