Small linux deployments

Read the rest of this entry »

I told myself when I started this blog that I was going to avoid simple howto posts and focus on system administration concepts. However, I’m going to break that rule today. I was looing through my referrer log files, and noticing that I get a lot of search queries for “How to…” or “how doI…” So, I dug up my access logs, fired up egrep, and made myself a list of search referrals with “how” in the string. Today I’m going to give in to the masses and attempt to answer some of them :

Linux how to execute simultaneous commands? how to run same command on multiple servers?

Clusterssh and shmux do this, as mentioned in a previous post. For a more scalable system, also have a look at puppet.

How to download 2.6.18-53.1.13 rhel?

run “yum update” to update all of your software packages. Be sure to restart after a kernel update.

Centos 5 : how to install tripwire?

Tripwire is a commercial product, so RTFM or bug support. Also see aide for a free version with similar design goals.

how do i enable rsh on rhel5?, how to configure rlogin in rhel5

Do you really want to do this? Might ssh/scp/rsync over ssh be a better option? The only possible reason is for speed in an isolated network, where every machine on the network is trusted.

Install the packages rsh-server and xinetd. edit /etc/xinetd.d/rsh and change disable = yes to disable = no. Add .rhosts files as needed. To enable rlogin, do the same for /etc/xinetd.d/rlogin

how to deactivate rsh on rhel 5

It isn’t installed by default. If it is installed, edit /etc/xinetd.d/rsh, /etc/xinetd.d/rlogin, and /etc/xinetd.d/rcp and add “disable = yes” to all of them. Or, just remove the whole package with “yum erase rsh”

how to check for kernel update rhel5

Run yum check-update , intuitively enough

How to deploy database in mysql in linux

1. Remove all flammable objects from the room.
2. Lift the protective clear plastic cover and push the “deploy database” button.
3. Take cover.

how to enable telnet in rhel5? how to install telnet on rhel5? how to enable the telnet on the rhel5 server?

Don’t. Use ssh instead and require remote shell users to download a putty or teraterm SSH if they are Windows users.

If you must, install the telnet-server package and enable the service in /etc/xinetd.d/telnet

Thanks to Andrew for the suggestion to add a plug for ssh here.

how to restrict other people from rebooting in linux?

1. Remove ca::ctrlaltdel:/sbin/shutdown -t3 -r now from /etc/inittab , or add a -a option to that line and put a list of users allowed to shut the system down in /etc/shutdown.allow
2. edit /etc/gdm/custom.conf and add the line SystemMenu = false to the [greeter] section

How to restrict root logins to the system console?

I assume you mean how to disable root ssh logins. open /etc/ssh/sshd_config and add a line “PermitRootLogin no” Addition: Also, set more restrictive permissions to /bin/su so that people can’t log into ssh as a normal user and su to root.

How to roll back centos kernel?

Since the old kernel should still be installed, simply edit /etc/grub.conf and change default=0 into default=1 Be sure to change it back when you get the kernel working, or you will perpetually be running one kernel behind current

how to set automatic updates on rhel5?

See my post on getting email notifications which I think is a better strategy. If you really must do automatic updates, create a daily crontab that runs yum -y update.

how to use yahoo messenger in linux el 5

pidgin.

and the junk bin…

• how to fix a mail size for sendmail in linux el5
• how to exploit apache serveur
• php mysqli href how to a link data from one side to another

Apple’s (in)famous for using somewhat bizarre internal codenames for their projects. Looks like they haven’t let us down with the iPhone SDK, apparently previously codenamed SquarePants. I just went to change my Apple password so I could download the iPhone SDK, and after I was finished I came across the following message:

Your Apple ID password has been changed

Select the “continue” button below to return to SquarePants Web Portal

Remember to change your internal product names everywhere they display before you bring a web application live. If they must be hard coded, put them in as few places as possible, or even better in a configuration system (like that ships with Zend Framework) that allows you to set development and production parameters separately.

Anyway, here’s a screenshot:

(click for full size)