Redhat Satellite 6.3 installation useful tips


Have you read Redhat Satellite 6.3 installation guide?

I usually like to read installation guides because they are full of useful tips! In this case I learned new interesting things about I/O performance for Satellite:

1) foreman-maintain utility. It checks the disk speed for Satellite /var sub-filesystems, for example:

# foreman-maintain upgrade check --target-version 6.2.z
...
Check for recommended disk speed of pulp, mongodb, pgsql dir.:
\ Finished
Disk speed : 80 MB/sec [OK]

( Take care about planning /var filesystem for your Satellite/Capsule installation. It will be one of the most stressed filesystems due the requested I/O )

2) The fantastic fio command! The previous ‘foreman-maintain’ utility uses fio command for the benchmarks. At the beginning it’s not easy to understand but it’s very powerful.
I suggest you to read more about fio and Satellite benchmarks checking this Redhat solution.
Let me know about your thoughts! 🙂

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Second blog opened!


Information Technology is one of my greater passions. Another one is to travel.. when I combine traveling and working together I feel myself excited like a child 🙂
From August I’m working on a second blog, http://www.enjoythestory.blog
My idea is to collect travel experiences and to share them between the users. I love to share vacations details and to read about them from other people.
If you like to share, let me know about it! I will create an account for you and you will publish everything u want. I need help because I will not have such a free time during the new job.
I’m waiting you!

Changing company


Starting from November I’ll work for a new company. Why I’m leaving Sinergy?
Basically I think it’s a good, solid company, but I met a big opportunity and I did not want to miss it.

I’m talking about Extraordy
Extraordy is the only company in Italy that works with Redhat official training and certifications. I’m talking about the opportunity to:

– work as offical Redhat trainer for platform/cloud/devops paths ( first I have to train myself as a trainer and I need to pass two exams, the goal is to reach the RHCI – Red Hat Certified Instructor certification )
– complete my RHCA path ( in Extraordy most of the people are RHCA ! )
– work and to grow as presale/architect and learning much possible about those roles
– work as consultant ( I can’t miss the technical tasks 😀 )
– research new technologies/products

At the same time I will travel around several cities in Italy, and I hope to work abroad, it would be a dream! I’d like it even if it is going to be just for a few days 🙂

RHEV 4.2: How to run commands via vdsm client


On RHV 4.2 can be useful to run commands via vdsm, especially during the troubleshooting. In my case I have a cluster where one hypervisor is in “Non Operational Status” due to a CPU missing flag inside the cluster.
On old releases I could use vdsClient command but now it has been replaced. It changed name and syntax:  now I can use vdsm-client command.

For example, How can I check CPU flags among the hypervisors? Easy to do!

# vdsm-client Host getCapabilities | grep -i flags
"cpuFlags": "fpu,vme,de,pse,tsc,msr,pae,mce,cx8,apic,sep,mtrr,pge,mca,cmov,pat,pse36,clflush,dts,acpi,mmx,fxsr,sse,sse2,ss,ht,tm,pbe,syscall,nx,pdpe1gb,rdtscp,lm,constant_tsc,arch_perfmon,pebs,bts,rep_good,nopl,xtopology,nonstop_tsc,aperfmperf,eagerfpu,pni,pclmulqdq,dtes64,monitor,ds_cpl,vmx,smx,est,tm2,ssse3,sdbg,fma,cx16,xtpr,pdcm,pcid,dca,sse4_1,sse4_2,x2apic,movbe,popcnt,tsc_deadline_timer,aes,xsave,avx,f16c,rdrand,lahf_lm,abm,3dnowprefetch,epb,cat_l3,cdp_l3,intel_pt,ibrs,ibpb,stibp,tpr_shadow,vnmi,flexpriority,ept,vpid,fsgsbase,tsc_adjust,bmi1,hle,avx2,smep,bmi2,erms,invpcid,rtm,cqm,rdt_a,rdseed,adx,smap,xsaveopt,cqm_llc,cqm_occup_llc,cqm_mbm_total,cqm_mbm_local,dtherm,ida,arat,pln,pts,spec_ctrl,intel_stibp,model_n270,model_Broadwell-IBRS,model_coreduo,model_SandyBridge-IBRS,model_Nehalem,model_Haswell-noTSX,model_Westmere-IBRS,model_Broadwell-noTSX,model_Haswell-noTSX-IBRS,model_Nehalem-IBRS,model_SandyBridge,model_core2duo,model_IvyBridge,model_Penryn,model_IvyBridge-IBRS,model_Westmere,model_Haswell-IBRS,model_Broadwell-noTSX-IBRS,model_Haswell,model_Conroe,model_Broadwell",

Let’s compare this ouput with the one from other hypervisors 😀

RHEV 4.2 metrics !!


From 4.2 release is possible to collect RHEV events and metrics from kibana.
The new metric store is not native, it must be manually installed. In my case I created a new guest inside RHEV and on top of it I installed the metric store. Basically it contains Elastic Search/Kibana running as container inside Openshift. Yes, you read well, Openshift! So, you will have a small Openshift running containing multiple containers. This is the installation guide

Following one screenshot of kibana examples dashboard:

RHEV 4.2 – Rhevm shell


From 4.2 release of Redhat Virtualization, rhevm shell is deprecated. You can still have the command but don’t use it because it “does not know” the new objects with new API version.
So, how can u deal and work about automation? The answer is: ansible!
This is a big opportunity for have fun using ansible. Where can you begin?
From the first, simple playbook:

- hosts: localhost
connection: local

tasks:
- name: Obtain SSO token
ovirt_auth:
url: "https://rhevm_url/ovirt-engine/api"
username: "admin@internal"
password: "insert_the_password"
insecure: "true"

- name: List vms
ovirt_vms_facts:
pattern: cluster=Default
auth: "{{ ovirt_auth }}"

- debug:
var: ovirt_vms

You have first to install ovirt-ansible-roles package, then you can run this playbook
It does not use external variables, it connects to rhevm via insecure mode, so this is the simpliest playbook you can use from rhevm to understand how it works.
This playbook will return each detail about vms running on rhevm. It’s extremely verbose but as I said this is just a start point 🙂

Have fun!

Linux Redhat 7: How to clear boot directory


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-
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 🙂