August 14, 2018

Linux Redhat 7: How to clear boot directory

Posted in Linux at 9:54 am by alessiodini


Recently I noticed that multiple Vmware Linux templates had /boot filesystem used more than 90%
If you look on the web u will find a lot of solutions based just on removing kernel rpms. I disagree !
I began to clear the /boot directory removing the oldest kernels but this was not enough.

At this point you must go to /boot directory and look for rescue files:

# ls | grep rescue

initramfs-0-rescue-b20d7fe5b15140269ad2c2e51af4735e.img

vmlinuz-0-rescue-b20d7fe5b15140269ad2c2e51af4735e

initramfs-0-rescue-80405299bcbc4ebabf5827a44c193.img

vmlinuz-0-rescue-80405299bcbc4ebabf5827a44c193

initramfs-0-rescue-d58aadc169974f0ea93d637c046d764b.img

vmlinuz-0-rescue-d58aadc169974f0ea93d637c046d764b

Each rescue file does not belong to any rpm package, so you can manually delete the oldest pair files. In order I suggest you to follow this actions:

1) Look for a single rescue pair. If you want to know which kernel does belong to, you can run lsinitrd initram-0-rescue-<id>
2) Try to boot the system using the rescue from the previous point
3) If everything worked fine, you can boot with the latest kernel and delete each old pairs rescue files.
4) Lastly, update the GRUB2 configuration:  grub2-mkconfig -o /boot/grub2/grub.cfg

Thank to Paolo Fruci and Marco Simonetti for helping me dealing with this issue, we played together 🙂

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June 21, 2018

Linux Redhat 6.10 released!!

Posted in Linux at 1:43 pm by alessiodini


Two days ago RHEL 6.10 was officially released.
Reading from the web I see new interesting features:

“This release also includes a Red Hat Enterprise Linux 6.10 base image
to help enterprises more easily migrate Red Hat Enterprise Linux 6
workloads into container-based applications. These cloud-native
workloads can then be deployed and maintained on a more modern
platform, including Red Hat Enterprise Linux 7, Red Hat Enterprise
Linux Atomic Host, and Red Hat OpenShift Container Platform.

To make it easier for customers to plan their migration to Red Hat
Enterprise Linux 7, Red Hat Enterprise Linux 6.10 provides updates to
the Pre-upgrade Assistant, Red Hat Upgrade Tool, and the accompanying
documentation. Learn more about the upgrade process and how to access”

I never migrated before a major RHEL release, can’t wait to play with 🙂

April 19, 2017

Got Certified!!!

Posted in Linux at 9:06 am by alessiodini


I passed the exam Redhat EX318!
Now I’m certified on RHEV as “RHCVA” – Redhat Certified Virtualization Administrator.
I have to thank a couple of friends: Giovanni Mancuso and Davide Giannlivigni, they helped me studying for the exam ( I did not take the course )

Thank you both!!!
😀

November 23, 2016

Redhat: How can I check virtualization prerequisites?

Posted in Linux at 11:45 am by alessiodini


Playing with virt commands, I found virt-host-validate .

It is very useful! If I run it from a virtual machine without nested virtualization enabled, I will have:

# virt-host-validate
QEMU: Checking for hardware virtualization : FAIL (Only emulated CPUs are available, performance will be significantly limited)
QEMU: Checking if device /dev/vhost-net exists : PASS
QEMU: Checking if device /dev/net/tun exists : PASS
QEMU: Checking for cgroup ‘memory’ controller support : PASS
QEMU: Checking for cgroup ‘memory’ controller mount-point : PASS
QEMU: Checking for cgroup ‘cpu’ controller support : PASS
QEMU: Checking for cgroup ‘cpu’ controller mount-point : PASS
QEMU: Checking for cgroup ‘cpuacct’ controller support : PASS
QEMU: Checking for cgroup ‘cpuacct’ controller mount-point : PASS
QEMU: Checking for cgroup ‘cpuset’ controller support : PASS
QEMU: Checking for cgroup ‘cpuset’ controller mount-point : PASS
QEMU: Checking for cgroup ‘devices’ controller support : PASS
QEMU: Checking for cgroup ‘devices’ controller mount-point : PASS
QEMU: Checking for cgroup ‘blkio’ controller support : PASS
QEMU: Checking for cgroup ‘blkio’ controller mount-point : PASS
QEMU: Checking for device assignment IOMMU support : WARN (Unknown if this platform has IOMMU support)
LXC: Checking for Linux >= 2.6.26 : PASS
LXC: Checking for namespace ipc : PASS
LXC: Checking for namespace mnt : PASS
LXC: Checking for namespace pid : PASS
LXC: Checking for namespace uts : PASS
LXC: Checking for namespace net : PASS
LXC: Checking for namespace user : PASS
LXC: Checking for cgroup ‘memory’ controller support : PASS
LXC: Checking for cgroup ‘memory’ controller mount-point : PASS
LXC: Checking for cgroup ‘cpu’ controller support : PASS
LXC: Checking for cgroup ‘cpu’ controller mount-point : PASS
LXC: Checking for cgroup ‘cpuacct’ controller support : PASS
LXC: Checking for cgroup ‘cpuacct’ controller mount-point : PASS
LXC: Checking for cgroup ‘cpuset’ controller support : PASS
LXC: Checking for cgroup ‘cpuset’ controller mount-point : PASS
LXC: Checking for cgroup ‘devices’ controller support : PASS
LXC: Checking for cgroup ‘devices’ controller mount-point : PASS
LXC: Checking for cgroup ‘blkio’ controller support : PASS
LXC: Checking for cgroup ‘blkio’ controller mount-point : PASS

November 16, 2016

Opensource day 2016!!

Posted in Linux tagged , at 1:33 pm by alessiodini


Yesterday I have been with colleagues at OpenSource Day in Rome!
It was first time for me and I was so funny following Redhat Speech, Labs and much more.
I also saw old and ex colleagues.
I took some picture:

Rome, Palazzo dei congressi

Me

Colleagues

August 4, 2016

Openbaton 2 Installation

Posted in Linux at 12:10 pm by alessiodini


Today I installed with a collegue a basic openbaton environment on a Ubuntu 16 server. Customer needs an NFV ETSI Orchestration environment. I began the task installing and configuring the basic modules, it was very easy and funny!

This is the dashboard 🙂

April 11, 2016

LPIC remote labs

Posted in Linux tagged , , , , , , , at 2:22 pm by alessiodini


I’m working on funny idea: looking on the web I read that a lot of people need linux systems to study for LPIC-1 exam. I want to make Centos and Ubuntu remote avaiable systems with a very very low price for the rent! With this method , each one can play and test LPIC-1 topics without have a full computer.
You just need a putty client or web browser , so even a tablet is enough 😉

March 10, 2016

Linux ACL & standard permission question

Posted in Linux at 10:07 am by alessiodini


After long time , yesterday I played a bit with ACL on Redhat 6.7 nodes.
Doing some experiment I saw a strange thing:


[root@node1 ~]# useradd pippo
[root@node1 ~]# touch alessio
[root@node1 ~]# chmod 400 alessio
[root@node1 ~]# setfacl -m u:pippo:rwx alessio

[root@node1 ~]# getfacl alessio
# file: alessio
# owner: root
# group: root
user::r--
user:pippo:rwx
group::---
mask::rwx
other::---

[root@node1 ~]# chmod 600 alessio
[root@node1 ~]# getfacl alessio
# file: alessio
# owner: root
# group: root
user::rw-
user:pippo:rwx #effective:---
group::---
mask::---
other::---

This could be a noob question… but why acl changes from rwx to —?
I suppose there is a relationship between ACL configured and those initial standard permissions.
I need to know more about it! 🙂

September 19, 2015

Redhat Openstack 7 Undercloud Installation Bug

Posted in Linux at 6:46 pm by alessiodini


In these days I’m working with Redhat Openstack 6/7 versions.

When I install the undercloud component i got this error:

WARNING: keystoneclient.auth.identity.generic.base Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
WARNING: keystoneclient.auth.identity.generic.base Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
WARNING: keystoneclient.auth.identity.generic.base Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
ERROR: openstack Could not determine a suitable URL for the plugin
+ openstack role create ResellerAdmin
WARNING: keystoneclient.auth.identity.generic.base Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
WARNING: keystoneclient.auth.identity.generic.base Discovering versions from the identity service failed when creating the password plugin. Attempting to determine version from URL.
ERROR: openstack Could not determine a suitable URL for the plugin
[2015-09-19 19:58:29,620] (os-refresh-config) [ERROR] during post-configure phase. [Command ‘[‘dib-run-parts’, ‘/usr/libexec/os-refresh-config/post-configure.d’]’ returned non-zero exit status 1]

[2015-09-19 19:58:29,621] (os-refresh-config) [ERROR] Aborting…
Traceback (most recent call last):
File “”, line 1, in
File “/usr/lib/python2.7/site-packages/instack_undercloud/undercloud.py”, line 526, in install
_run_orc(instack_env)
File “/usr/lib/python2.7/site-packages/instack_undercloud/undercloud.py”, line 461, in _run_orc
_run_live_command(args, instack_env, ‘os-refresh-config’)
File “/usr/lib/python2.7/site-packages/instack_undercloud/undercloud.py”, line 297, in _run_live_command
raise RuntimeError(‘%s failed. See log for details.’, name)
RuntimeError: (‘%s failed. See log for details.’, ‘os-refresh-config’)
ERROR: openstack Command ‘instack-install-undercloud’ returned non-zero exit status 1

I read a lot of times the official documentation and I looked on Redhat Solutions but I got stuck here.
With some analisys I found that if I add the netmask on undercloud_public_vip and undercloud_admin_vip directives the script uses the ip with the whole netmask:
( undercloud.conf)

undercloud_public_vip = 172.16.111.2/24
undercloud_admin_vip = 172.16.111.3/24

(…)
++ export OS_AUTH_URL=https://172.16.111.2/24:13000/v2.0
++ OS_AUTH_URL=https://172.16.111.2/24:13000/v2.0
++ hiera controller_public_vip
+ REGISTER_SERVICE_OPTS=’-p 172.16.111.2/24′
++ hiera controller_public_vip
+ INIT_KEYSTONE_OPTS=’-s 172.16.111.2/24′

Thats’ why the command gets an error!!!

If I don’t write the netmasks the command will configure both ip with /32 netmask!!!!

I updated the Redhat bug 1251271, I’m curious to see what Redhat will reply :))

September 4, 2015

Redhat Ceph Storage

Posted in Linux at 2:26 pm by alessiodini


From a couple of weeks I’m playing with Redhat Ceph Storage, experimenting the cluster and some feature but at the moment I need to reinstall all the systems because I destroyed them!! 🙂

I’m also interested in adding Ceph to Openstack and play with both together.
Starting from next week I will have 6 physical systems available for this purpose… let’s see what will happen! 🙂

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