Showing posts with label linux. Show all posts
Showing posts with label linux. Show all posts

Tuesday, March 5, 2019

Customizing bash command line completion

What am I talking about?

In the bash shell on Linux, you can type a character or two then hit the TAB key to get a list of the commands that start with those characters. You can do the same to complete the name of a file you're trying to edit or directory you're trying to change to. It turns out that you can customize this command line completion behavior by installing the "bash-completion" package. This package is often installed by default and has been available for several years.

What can you do with bash-completion?

You can have the TAB key complete command arguments for you. For example, the 'curl' command has tons of arguments. You can customize bash to auto-complete the parameters for you. You just need to create a specifically coded file named 'curl' in the /etc/bash_completion.d folder. Here's a great tutorial on creating these command completion scripts:


Even more helpful, here is a ton of them that have already been created:


If you've got a command with tons of options, you can use this to make it easier for you or your users to successfully create a working command.

Thursday, September 8, 2016

Installing IBM Control Desk 7.6 on RHEL 6.5 in a test environment

The biggest hitch you'll encounter when installing ICD 7.6 on Redhat Linux in a dev/test environment is the error

CTGIN8264E : Hostname failure : System hostname is not fully qualified

And the reason it's a big hitch is because the error is misleading. You do need to have your hostname set to your FQDN, but you also need to have an actual DNS (not just /etc/hosts, but true DNS) A record for your hostname. If you don't already have one that you can update, you can install the package named:

The Berkeley Internet Name Domain (BIND) DNS (Domain Name System) server

It is available on the base Redhat install DVD.

Tuesday, April 19, 2016

Installing IBM Control Desk v7.6 on Red Hat Enterprise Linux 6.6

I just had a difficult time installing ICD 7.6 on RHEL 6.6 and wanted to share one workaround that I used that finally got me around the prerequisite checker failures on Installation Manager.

I've done this successfully in a production environment, but in this case I'm installing this in a VM in my lab that's running under VMWare Workstation, and it's on a NAT network. Every time the Installation Manager runs the prerequisite checker, I kept getting a failure on network.fqdn, even though the hostname was absolutely set to a fully qualified domain name (icd76.mynet.foo). So I started up 'dnsmasq' locally and pointed to my own IP address as my DNS server. That allowed network.fqdn to PASS, but then network.dns would FAIL (!).

Figuring I have my networking configured "good enough" for my small test machine, I simply edited the following files:

PAD_07060000.cfg
PAW_07060000.cfg

in the directory /var/ibm/InstallationManager/bundles/plugins/com.ibm.tivoli.pae.prereq 1.0.1.20157141414/com/ibm/tivoli/pae/prereq/SystemRequirements/unix/ to change:

network.dns=True

to

network.dns=False

And then it worked like a champ!

How did you find those buried files?

If you cd to /var/ibm/InstallationManager/logs and run 'firefox index.xml', you get a great view of all of the Installation Manager log files. In the latest one, the completion message pointed me basically to that directory.

Friday, November 6, 2015

ICO 2.5: Creating a Red Hat 6.5 image with Gnome for use with a VMWare vSphere cloud

Introduction

When creating your private OpenStack-managed vSphere cloud, you're going to need some "images" ("VM Templates" in VMWare terminology) so you can launch/deploy instances. The really sticky part about this configuration is that OpenStack has traditionally only supported the KVM hypervisor, which uses a different disk format than VMWare (KVM uses QCOW2 and VMWare uses VMDK). I found some great QCOW2 images here: http://docs.openstack.org/image-guide/content/ch_obtaining_images.html and some great CentOS VMDK images here: http://osboxes.org. I had some different hurdles with each of those and finally decided just to install RHEL 6.5 from scratch, then modify that VM to work, then create a VM Template that would be automatically discovered by OpenStack as an image. In this post I'll cover the highlights of this technique.

Install Red Hat

Install the "Desktop" option. This will mean that you have to do a little cleanup later, but I'll cover that.

Install VMWare Tools

Go ahead and install VMWare tools just to make your life a little easier.

Configure Yum Repositories and Install Packages

If you're using Red Hat Subscription Manager, you don't have to go through these steps. If you're not using RHSN, you'll need to manually configure some repositories. I found for this exercise that the CentOS repositories, along with the EPEL repository, worked great. To configure the CentOS repositories, create a file named /etc/yum.repos.d/YOU_PICK_A_NAME.repo with the following contents:

[base]
name=CentOS-6 - Base
mirrorlist=http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=os
#baseurl=http://mirror.centos.org/centos/6/os/x86_64/
gpgcheck=0

#released updates
[updates]
name=CentOS-6 - Updates
mirrorlist=http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=updates
#baseurl=http://mirror.centos.org/centos/6/updates/x86_64/
gpgcheck=0

#additional packages that may be useful
[extras]
name=CentOS-6 - Extras
mirrorlist=http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=extras
#baseurl=http://mirror.centos.org/centos/6/extras/x86_64/
gpgcheck=0

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6 - Plus
mirrorlist=http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=centosplus
#baseurl=http://mirror.centos.org/centos/6/centosplus/x86_64/
gpgcheck=0
enabled=0

#contrib - packages by Centos Users
[contrib]
name=CentOS-6 - Contrib
mirrorlist=http://mirrorlist.centos.org/?release=6&arch=x86_64&repo=contrib
#baseurl=http://mirror.centos.org/centos/6/contrib/x86_64/
gpgcheck=0
enabled=0

Then run 'yum repo-list' to verify the repositories were created. Now you can run the following commands:

yum -y epel-release
yum -y cloud-init
yum -y cloud-utils
yum -y heat-cfntools

Configure Networking

Since the "Desktop" option was chosen, the NetworkManager service was installed and enabled. You need to change that with these commands:

service NetworkManager stop
chkconfig NetworkManager off
service network start
chkconfig network

Now run the following commands so that eth0 will get configured properly:

sed -i '/^HWADDR/d' /etc/sysconfig/network-scripts/ifcfg-eth0
echo -n > /etc/udev/rules.d/70-persistent-net.rules
echo -n > /lib/udev/rules.d/75-persistent-net-generator.rules

Configure cloud.cfg

The default configuration will try to contact multiple non-existent IP addresses for metadata, and you don't need that by changing /etc/cloud/cloud.cfg. Add the following line to that file:

datastore_list: [ NoCloud, ConfigDrive, None ]

You *may* also want to set:

disable_root: 0
ssh_pwauth: 1

This will allow you to access the VM as root, and via ssh with a password.

Make a Template

Via the vSphere Web Client or vSphere Windows Client, clone the VM to a template. After you do this, wait a few minutes for OpenStack to "see" this new template as an Image.

Conclusion

Following the above steps should get you a working template from which you can explore the other capabilities of ICO and ICMWO.