Trying to allocate 1005 pages for VMLINUZ error when booting with RHEL or CentOS 6.5 disks

 

I was booting the RHEL 6.5 or CentOS 6.5 on a IBM PureFlex System and I have this error. This occurs when When installing Red Hat Enterprise Linux 6 from DVD media the installation will default to native Extensible Firmware Interface (EFI) mode boot. I do not have

According to IBM Website, 

The workaround is simply to install the operating system in the traditional legacy mode, since there is generally no reason to install in other than Legacy mode. The workaround is only necessary if the media you are booting defaults to EFI mode (DVD or EFI Preboot eXecution Environment (PXE)) otherwise a legacy installation (e.g. - traditional PXE) is the default and is unaffected by this issue.

To force a legacy installation of the operating system from the EFI bootable DVD media the user should:

    Press F12 key when the IBM splash screen is shown during system boot.
    Select Legacy Only option and press Enter.
    The operating system will boot and install in traditional legacy boot mode.

And the issue was resolved.

References:

1. Red Hat Enterprise Linux 6 (RHEL6) native Extensible Firmware Interface (EFI) install is not supported with greater than 512 GB memory - IBM System x and BladeCenter
2. Bug 691860 - UEFI version of ISO fails to boot when >4gig (since f14)

Location of GPFS Client Log file

The location of the GPFS Log file is located at the /var/adm/ras/mmfs.log.latest. You can find a wealth of information of errors and information. When you are monitoring the errors in real time, you may want to use the tail -f to see the real time troubleshooting

# tail -f /var/adm/ras/mmfs.log.latest

Accurately Time Your Parallel Loops in OpenMP

Learn how to use a wall clock timer that is included as part of the OpenMP library. Jeff Cogswell walks you through how. Taken from Accurately Time Your Parallel Loops in OpenMP which is found http://goparallel.sourceforge.net/

GPFS Autoconfig Error on CentOS 6

When I try to build the portability layer for GPFS which is done by

make LINUX_DISTRIBUTION=REDHAT_AS_LINUX Autoconfig

 There are errors like the ones below

cd /usr/lpp/mmfs/src/config; ./configure --genenvonly; /usr/bin/cpp -P def.mk.proto > ./def.mk; exit $? || exit 1
Cannot find a valid kernel include dir
def.mk.proto:12:19: error: env.mcr: No such file or directory
make: *** Autoconfig Error 1

The solution is to make sure you have all the package installed. These are the following prerequistics

kernel-headers-2.6.18-128.el5.x86_64.rpm
kernel-devel-2.6.18-128.el5.x86_64.rpm
libgomp-4.3.2-7.el5.x86_64.rpm
glibc-headers-2.5-34.x86_64.rpm
glibc-devel-2.5-34.x86_64.rpm
gcc-4.1.2-44.el5.x86_64.rpm
libstdc++-devel-4.1.2-44.el5.x86_64.rpm
gcc-c++-4.1.2-44.el5.x86_64.rpm

References:

1. Linux system does not have prerequisite kernel or C++ packages 

Accurately Time Your Parallel Loops in OpenMP

There is an interesting video by Go Parallel Site on "Accurately Time Your Parallel Loops in OpenMP".

I have embedded the URL here

NFS mount errors with "clnt_create: RPC: Unknown host" for CentOS 6

When attempting to mount CentOS 6, my mount fails with

clnt_create: RPC: Unknown host

Diagnostic:
If we do a more thorough diagnostic, this is the issue

# showmount -e  
clnt_create: RPC: Unknown host  
# showmount -e localhost  
Export list for localhost:  
/export/my_data \* 

Resolution:

Taken from Redhat Site

Implement forward and reverse lookups (A records and CNAME records) in DNS and have the system point towards the DNS servers. Implement for both IPv4 and IPv6. If unable to resolve DNS issues, change the /etc/hosts file from this:

Change from 

::1          localhost localhost.localdomain localhost6 localhost6.localdomain6

To

::1          machine_hostname localhost localhost.localdomain localhost6 localhost6.localdomain6

Restart the NFS service and check on the showmount -e localhost and showmount -e and attempt to mount the share.

# service nfs restart  
# showmount -e localhost  
# showmount -e 

Ganglia – error collecting data (127.0.0.1:8652): fsockopen error: Connection refused

If you are having issues after installing Ganglia according to the Blog  Installing and Configuring Ganglia on CentOS 5.8, and if you are facing errors like Ganglia – error collecting data (127.0.0.1:8652): fsockopen error: Connection refused 

First thing do take a look at whether you have the necessary ganglia and rrdcached userid and group in your /etc/passwd and /etc/shadow. You should have something lines like thie

/etc/passwd

..... 
rrdcached:x:101:445:rrdcached:/var/rrdtool/rrdcached:/sbin/nologin
ganglia:x:102:446:Ganglia Monitoring System:/var/lib/ganglia:/sbin/nologin

At /etc/group

rrdcached:x:445:
ganglia:x:446:

Make sure your /var/lib/ganglia permission is

drwxr-xr-x 4 ganglia ganglia 4096 Aug 19 10:47 rrds

Or you can change permission if your permission is not correct

# chown -Rv ganglia.ganglia rrds

Using iblinkinfo to report link infomation for all links in the fabric

The command iblinkinfo is a useful command to give a good overview of link information for all links in the fabric

[root@node-h00 ~]# iblinkinfo
CA: node-c27 HCA-1:
      0xxxxxxxxxxxxxxx     24    1[  ] ==( 4X          10.0 Gbps Active/ ..... 
CA: node-c26 HCA-1:
      0xyyyyyyyyyyyyyyy    22    1[  ] ==( 4X          10.0 Gbps Active/ ..... 
CA: node-c25 HCA-1:
      0xzzzzzzzzzzzzzzz     29    1[  ] ==( 4X          10.0 Gbps Active/ .....
CA: node-c24 HCA-1:
      0xaaaaaaaaaaaaaaa     28    1[  ] ==( 4X          10.0 Gbps Active/ .....
CA: node-c25 HCA-1:
      0xsssssssssssssss     27    1[  ] ==( 4X          10.0 Gbps Active/ .....
...................
...................
...................

Step 2: Print all information on each node on one single line

[root@node-h00 ~]# iblinkinfo -l 

0xaaaaaaaaaaaaaaaa "          node-c26 HCA-1"     22    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   29[  ] "IBM HSSM" ( )
0xvvvvvvvvvvvvvvvv "          node-c25 HCA-1"     29    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   28[  ] "IBM HSSM" ( )
0xbbbbbbbbbbbbbbbb "          node-c24 HCA-1"     28    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   27[  ] "IBM HSSM" ( )
0xcccccccccccccccc "          node-c23 HCA-1"     27    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   26[  ] "IBM HSSM" ( )
0xdddddddddddddddd "          node-c20 HCA-1"     26    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   25[  ] "IBM HSSM" ( )
0xeeeeeeeeeeeeeeee "          node-c21 HCA-1"     23    1[  ] ==( 4X          10.0 Gbps Active/  LinkUp)==>  0xswitchfa     19   24[  ] "IBM HSSM" ( )

.....
.....
.....

Step 3: List Down Ports in the Fabric

[root@strawberry-h00 ~]# iblinkinfo -d

Switch: swswswswswswss IBM HSSM:
          19   16[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          19   19[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          19   23[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          19   31[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          19   32[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          19   33[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          19   34[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          19   35[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          19   36[  ] ==(                Down/Disabled)==>             [  ] "" ( )
Switch: swswswswswswswsw IBM HSSM:
          16   31[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          16   32[  ] ==(                Down/ Polling)==>             [  ] "" ( )
          16   33[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          16   34[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          16   35[  ] ==(                Down/Disabled)==>             [  ] "" ( )
          16   36[  ] ==(                Down/Disabled)==>             [  ] "" ( )

For all information:

1. iblinkinfo(8) - Linux man page  

Create export domain or ISO Domain on RHEV 3

This is taken from Red Hat Portal How to create an export domain or iso domain? (Need customer access) On the NFS, you need to do the following

# mkdir /export/data
# chown -R 36:36 /export/data
# chmod 755 /export/data
# vim /export_data
/export/data *(rw)
# /etc/init.d/nfs restart
# chkconfig nfs on

The key setup is that the ownership must be given vdsm kvm (36:36). Or you will have errors like "Error while executing action Add Storage Connection: Problem while trying to mount target"

# mkdir /export/ISO 
# chown -R 36:36 /export/ISO 
# chmod 755 /export/ISO 
# vim /export/ISO /export/ISO *(rw) 
# /etc/init.d/nfs restart 
# chkconfig nfs on

References:

1. Red Hat Enterprise Virtualisation and NFS (NetApp Community)
2. How to create an export domain or iso domain? (Red Hat Portal - Restricted Access)

Subscribing to Red Hat Virtualisation Manager Channels

Taken from Red Hat Red Hat Enterprise Visualization Documentation Step 1: Register the system with Subscription Manager Run the following command and enter your Red Hat Network user name and password to register the system with the Red Hat Network

subscription-manager register

Step 2: Identify Available Entitlement Pools Entitlement pools containing the channels required to install the Red Hat Enterprise Virtualization Manager

# subscription-manager list --available | grep -A8 "Red Hat Enterprise Linux Server"
# subscription-manager list --available | grep -A8 "Red Hat Enterprise Virtualization"

Step 3: Attach Entitlement Pools to the System Use the pool identifiers located in the previous step to attach the Red Hat Enterprise Linux Server and Red Hat Enterprise Virtualization entitlements to the system. Run the following command to attach the entitlements:

# subscription-manager attach --pool=[POOLID]

Step 4: Enable the Required Channels Run the following commands to enable the channels required to install Red Hat Enterprise Virtualization:

# yum-config-manager --enable rhel-6-server-rpms
# yum-config-manager --enable rhel-6-server-supplementary-rpms
# yum-config-manager --enable rhel-6-server-rhevm-3.4-rpms
# yum-config-manager --enable jb-eap-6-for-rhel-6-server-rpms

Mapping Ad account to Local Linux Group with Centrify Express on CentOS 6

Step 1. In order to add the AD User to the local User Group adduser command is not nsswitch aware and do not recognize a user not locally defined when adding someone to a group.

# vim /etc/group

.....
.....
users:x:100:user1,user2

Step 2: Edit /etc/centrifydc/centrifydc.conf Edit /etc/centrifydc/centrifydc.conf, uncomment and change the following parameter to true

# Merge local group membership from /etc/group into the Centrify group
# response for groups with the same name and gid.  This violates the NSS
# interface behavior and may have unexpected side effects, so it is
# disabled by default. You must run adreload to detect changes
# in the local group file.
#
adclient.local.group.merge:true

Step 3: Centrify Load and Flush

# adreload && adflush

Step 4: Check and verify. Logon as user1

$ id -a
uid=.........gid=.......... 100(users) .....................

References:

1. How to Add AD user local group

-bash: nslookup: command not found on CentOS

If you install Basic Server, you may not get the packages like nslookup and dig. to install the packages, do the followings:

# yum install bind-utils

Add an Active Directory (AD) Domain Account to sudo on Centrify Express for CentOS 6

Adding a Active Directory (AD) Domain Account to /etc/sudo is fairly easy on Centrify Express for CentOS 6. Suppose you have an AD Group called "Sys_Admin", just add it to the

.....
## Allow root to run any commands anywhere
root    ALL=(ALL)       ALL
%System_Admin ALL=(ALL)       ALL
.....

If it is an individual user, just get the userid from Active Directory

# getent passwd myuserid
user1:x:122:122:User1 Name:/home/user1:/bin/centrifyda

Update /etc/sudoers

.....
## Allow root to run any commands anywhere
root    ALL=(ALL)       ALL
%user1 ALL=(ALL)       ALL
.....

Do a final check on whether the sudo is working fine by doing

# sudo -l

Matching Defaults entries for user1 on this host:
requiretty, !visiblepw, always_set_home, env_reset, env_keep="COLORS
DISPLAY HOSTNAME HISTSIZE INPUTRC KDEDIR LS_COLORS", env_keep+="MAIL PS1
PS2 QTDIR USERNAME LANG LC_ADDRESS LC_CTYPE", env_keep+="LC_COLLATE
LC_IDENTIFICATION LC_MEASUREMENT LC_MESSAGES", env_keep+="LC_MONETARY
LC_NAME LC_NUMERIC LC_PAPER LC_TELEPHONE", env_keep+="LC_TIME LC_ALL
LANGUAGE LINGUAS _XKB_CHARSET XAUTHORITY",
secure_path=/sbin\:/bin\:/usr/sbin\:/usr/bin

User user1 may run the following commands on this host:
(ALL) ALL

Enabling Debugging for Linux Systems for Centrify Express on CentOS 6

If you are using centrify-free,  here are some tips to enable debugging. You can also watch the Youtube version from Centrify. See under the reference session

 Step 1: Enable Debugging for Centrify

# /usr/share/centrifydc/bin/addebug on
/var/log/centrify_client.log does not exist. Creating now.
Configure /etc/rsyslog.conf
Send HUP signal to rsyslogd
Configure log level in /etc/centrifydc/centrifydc.conf
Reload /etc/centrifydc/centrifydc.conf
Centrify DirectControl debug logging is on

Step 2: Collect support information via adinfo_extra.sh

# adinfo --support

Collecting stack trace information via stacktrace.pl:

Collecting support information via adinfo_extra.sh:
Collecting information for adinfo --support now...
Collection finished. Compress now.
Successfully gzip /var/centrify/tmp/adinfo_support.tar

Step 3: Disable Debugging for Centrify

# /usr/share/centrifydc/bin/addebug off
Configure /etc/rsyslog.conf
Send HUP signal to rsyslogd
Configure log level in /etc/centrifydc/centrifydc.conf
Reload /etc/centrifydc/centrifydc.conf
Centrify DirectControl debug logging is off

Step 4: Check the file

# ls  -al /var/centrify/tmp/adin_support.tar.gz

References:

1. Centrify Express: Enabling Debugging for Linux Systems