Finding out command line parameters to a linux kernel module (modinfo)

Command line: 
  modinfo bonding

Output: 
  filename:       /lib/modules/2.6.32-400.36.4.el5uek/kernel/drivers/net/bonding/bonding.ko
  author:         Thomas Davis, tadavis@lbl.gov and many others
  description:    Ethernet Channel Bonding Driver, v3.6.0
  version:        3.6.0
  license:        GPL
  srcversion:     765520422A582FCDBFBC802
  depends:        ipv6
  vermagic:       2.6.32-400.36.4.el5uek SMP mod_unload modversions
  parm:           max_bonds:Max number of bonded devices (int)
  parm:           tx_queues:Max number of transmit queues (default = 16) (int)
  parm:           num_grat_arp:Number of gratuitous ARP packets to send on failover event (int)
  parm:           num_unsol_na:Number of unsolicited IPv6 Neighbor Advertisements packets to send on failover event (int)
  parm:           miimon:Link check interval in milliseconds (int)
  parm:           updelay:Delay before considering link up, in milliseconds (int)
  parm:           downdelay:Delay before considering link down, in milliseconds (int)
  parm:           use_carrier:Use netif_carrier_ok (vs MII ioctls) in miimon; 0 for off, 1 for on (default) (int)
  parm:           mode:Mode of operation : 0 for balance-rr, 1 for active-backup, 2 for balance-xor, 3 for broadcast, 4 for 802.3ad, 5 for balance-tlb, 6 for balance-alb (charp)
  parm:           primary:Primary network device to use (charp)
  parm:           primary_reselect:Reselect primary slave once it comes up; 0 for always (default), 1 for only if speed of primary is better, 2 for only on active slave failure (charp)
  parm:           lacp_rate:LACPDU tx rate to request from 802.3ad partner (slow/fast) (charp)
  parm:           ad_select:803.ad aggregation selection logic: stable (0, default), bandwidth (1), count (2) (charp)
  parm:           xmit_hash_policy:XOR hashing method: 0 for layer 2 (default), 1 for layer 3+4 (charp)
  parm:           arp_interval:arp interval in milliseconds (int)
  parm:           arp_ip_target:arp targets in n.n.n.n form (array of charp)
  parm:           arp_validate:validate src/dst of ARP probes: none (default), active, backup or all (charp)
  parm:           fail_over_mac:For active-backup, do not set all slaves to the same MAC.  none (default), active or follow (charp)
  parm:           all_slaves_active:Keep all frames received on an interfaceby setting active flag for all slaves.  0 for never (default), 1 for always. (int)
  parm:           resend_igmp:Number of IGMP membership reports to send on link failure (int)

Failed to get connection to session: Failed to connect to socket /tmp/dbus: Connection refused (virt-manager)

Problem: 
  virt-manager cannot be started after fresh install due to a bug on dbus.

Fix, recreate machine id: 
  dbus-uuidgen > /var/lib/dbus/machine-id

Ref: 
  http://bugs.centos.org/view.php?id=5334
  https://bugzilla.redhat.com/show_bug.cgi?id=598200
  http://nutanix.blogspot.com/2013/06/kvm-virt-manager-startup-failure.html
 

Interactive on RHEL / Centos 7 (grub2)

Edit boot entry
  At boot menu, press "e" to edit a boot entry, go to the line beginning with "linux".

Add "systemd.confirm_spawn=1", remove "rhgb quiet"
  linux16 /vmlinuz-3.10.0-123.9.3.el7.x86_64 root=/dev/mapper/ol-root ro crashkernel=auto vconsole.font=latarcyrheb-sun16 rd.lvm.lv=ol/swap rd.lvm.lv=ol/root vconsole.keymap=us rhgb quiet LANG=en_US.UTF-8 systemd.confirm_spawn=1

Continue to boot up linux
  Press ctrl-x to continue the boot process. The system will now ask interactively which services are to be started.

Create, list, and extract archives under Linux (tar, star, gzip, bzip2)

Create Archive: 
  tar -cvf tmp.tar tmp
  star -c -f=tmp.star tmp

Create Archive, and with compression: 
  tar -cvf - tmp | gzip > tmp.tar.gz
  star -c tmp | bzip2 > tmp.star.bz2

List Archive: 
  star -t -f=tmp.star
  tar -tvf tmp.tar

List Archive, and with compression: 
  gzip -cd tmp.star.gz | star -t
  bzip2 -cd tmp.tar.bz2 | tar -tvf -

Extract Archive: 
  tar -xvf tmp.tar
  star -x -f=tmp.star

Extract Archive, and with compression: 
  gzip -cd tmp.tar.gz  | tar -xvf  -
  bzip2 -cd tmp.star.bz2 | star -x

GitHub: setup new account, create repo, sync from linux

Create an account on GitHub
   https://github.com/join

Add an SSH key
   https://help.github.com/articles/generating-ssh-keys/

Create new repo
  https://help.github.com/articles/create-a-repo/

Install git client on linux
  yum -y install git-core

Setup username and email
  git config --global user.name 'biggie'
  git config --global user.email 'void@space.null'

Clone the new repo
  git clone git@github.com:biggie/juicy.git /tmp/juicy

Add modified files
  (some changes)
  git add .

Commit changes to local repo
  git commit -m 'Tell me what happened'

Push changes back to GitHub
  git push

Verify change logs
  git log

Grub: Windows multi boot, mutually exclusive partitions

Suppose we have this filesystem layout:

  (hd0,0) - Centos 6
  (hd0,1) - Windows Server 2003
  (hd0,2) - Windows Server 2003
  (hd0,3) - Windows Server 2012

In /etc/grub.conf, insert or update the following boot entries for windows (centos is already present):

  title windows 2003 (hd0,1)
    unhide (hd0,1)
    hide (hd0,2)
    hide (hd0,3)
    rootnoverify (hd0,1)
    chainloader +1
    makeactive

  title windows 2008 (hd0,2)
    hide (hd0,1)
    unhide (hd0,2)
    hide (hd0,3)
    rootnoverify (hd0,2)
    chainloader +1
    makeactive

  title windows 2012 (hd0,3)
    hide (hd0,1)
    hide (hd0,2)
    unhide (hd0,3)
    rootnoverify (hd0,3)
    chainloader +1
    makeactive

When any one windows boots up, all other windows partitions will be hidden, and therefore be protected from any unwanted modifications.

Puppet Module: adding cron jobs, software packages, services

Node configuration (Default, and Individual node)
# site.pp

Package {
  allow_virtual => true,
}

# Install update job and ntp to all nodes
node default {
  include apps::update
  include apps::ntp
}

# Install tomcat6 and httpd to tomcat1.lan
node 'tomcat1.lan' {
  include apps::ntp
  include apps::update
  include apps::tomcat6
  include apps::httpd
}

Module and Class Configuration
# apps/init.pp

# Cron jobs for OS and puppet update.
class apps::update {
  cron { yum-update:
    command => "/usr/bin/yum -y update",
    user    => root,
    minute  => "*/5"
  }

  cron { puppet-update:
    command => "/usr/bin/puppet agent --test",
    user    => root,
    minute  => "*/5"
  }
}

# Auto install, and auto start-up
class apps::ntp {
  package { 'ntp': ensure => installed }

  service { "ntpd":
    ensure => running,
    enable => true,
    subscribe => Package["ntp"]
  }
}

class apps::httpd {
  package { 'httpd': ensure => installed }

  service { "httpd":
    ensure => running,
    enable => true,
    pattern => "httpd",
    subscribe => Package["httpd"]
  }

}

# Same as above, resolved package dependencies.
class apps::tomcat6 {
  package { 'tomcat6': ensure => installed }
  package { 'glibc-headers': ensure => installed }
  package { 'kernel-headers': ensure => installed }

  Package['kernel-headers'] -> Package['glibc-headers'] -> Package['tomcat6']

  service { "tomcat6":
    ensure => running,
    enable => true,
    pattern => "tomcat6",
    subscribe => Package["tomcat6"]
  }

}

Install puppet on centos linux 6

Install puppet yum repo
rpm -ivh https://yum.puppetlabs.com/el/6.5/products/x86_64/puppetlabs-release-6-10.noarch.rpm
rpm -ivh https://yum.puppetlabs.com/el/7/products/x86_64/puppetlabs-release-7-10.noarch.rpm

Install Puppet Client
yum -y install puppet
chkconfig puppet on
service puppet restart

Install Puppet Master
yum -y install puppet-server
chkconfig puppetmaster on
service puppetmaster restart

Setup Firewall Exception
iptables -I INPUT 4 -m state --state NEW -m tcp -p tcp --dport 8140 -j ACCEPT
service iptables save
service iptables restart

Request a New Certificate (on Client)
puppet agent --ca_server puppet1.lan

Sign the Certificate Request (on Server)
puppet ca sign tomcat1.lan

Setup Puppet Master Location (on Client)
echo "server = puppet1.lan" >> /etc/puppet/puppet.conf
service puppet restart

Install First Manifest (on Server)
cat << EOF > /etc/puppet/manifests/site.pp
# site.pp
    cron { yum-update:
      command => "/usr/bin/yum -y update",
      user    => root,
      minute  => "*/1"
    }
EOF

Validate Syntax of Manifest (on Server)
puppet parser validate /etc/puppet/manifests/site.pp

Pull, and Apply Manifest (on Client)
puppet agent  --verbose –test

Trigger an alert from windows eventlog, with event text as message

Step-1: Create a Job which will trigger on an Event during specific condition

Step-2: Right Click on the job and Export it, save it as test.xml

Step-3: Open test.xml File in notepad to Edit, Find (Event Trigger)

Step-4: Include ValueQueries as shown below, save the file. In below example, I have added (Event/EventData/Data) as (EventData) which will be used as $EventData while sending a mail.

Tip:

You can include any values in the event (Example: Event/System/Computer will include your Server Name). You can open the event -> Go to Details Tab -> Select XML view to see more details:

Step-5:

Delete the existing task and import the new task using modified XML file.

 

Step-6:

Edit Actions -> Send an e-mail option, include $(EventData) as appropriate

好老師捨身救活四學生

【本報訊】在大地震中，無數的學校被無情的震倒，而一個個老師犧牲了性命救活學生的偉大故事，卻成了今次悲劇中的禮讚。

在德陽市漢旺鎮一間學校任職教導主任的譚千秋老師（50歲），在前日（周二）晚上10時許，救援人員從倒塌校舍的瓦礫中將他的屍體挖掘出來。救援人員說：「我們發現他的時候，他雙臂張開趴在課桌上，身體死死地護着四名學生，四名學生都活下來了。」其中一名獲救高中二女生劉紅麗的舅舅事後說：「他可是個大好人，大英雄呀!」譚老師的妻子撫着丈夫的屍體，替他拭去臉上每一粒沙塵，為他整理蓬亂的頭髮，譚老師的後腦被石頭壓得深凹下去……譚妻哭不成聲：「那天早上他和平常一樣，6點就起來，給我們小女兒洗漱穿戴好，帶着她出去散步，然後早早上班，這一走就再也沒回來了。」

用背擋住水泥板

遵道鎮歡歡幼稚園在地震中完全倒塌，當時有80多名孩子午睡，事件中共有50多名小孩和3名老師死亡，瞿萬容老師是其中一名死者，當時她用背部擋住垮塌的水泥板，懷裏還緊抱着一名小孩。幼稚園校長李娟哭說：「小孩獲救了，但瞿老師就永遠離開了我們。」