How Do I Install
Ksplice?
First, you need to
register with Ksplice. Type the following command to install rpm repo
under RHEL 5:
# rpm -ivh
https://www.ksplice.com/yum/uptrack/centos/ksplice-uptrack-release.noarch.rpm
To install Ksplice,
enter:
# yum install
uptrack
Edit
/etc/uptrack/uptrack.conf, enter:
# vi
/etc/uptrack/uptrack.conf
Update it as follows
(input your access key):
[Auth]
accesskey =
ADD-YOUR-ACCESS-KEY-HERE
[Network]
# Proxy to use when
accessing the Uptrack server, of the form
#
[protocol://][:port]
# The proxy must
support making HTTPS connections. If this is unset,
# Uptrack will look
for the https_proxy, HTTPS_PROXY, and http_proxy
# environment
variables in that order, and then finally look for a
# proxy setting in
the system-wide GConf database, if available.
https_proxy =
[Settings]
# Automatically
install updates at boot time. If this is set, on
# reboot into the
same kernel, Uptrack will re-install the same set of
# updates that were
present before the reboot.
install_on_reboot =
yes
# Options
configuring the Uptrack cron job.
#
# GUI users will get
all notices via the GUI and likely want to set
# the following cron
options to "no".
# Cron job will
install updates automatically
autoinstall = no
# Cron job will
print a message when new updates are installed.
# This option is
only relevant if autoinstall = yes
cron_output_install
= no
# Cron job will
print a message when new updates are available
cron_output_available
= no
# Cron job will
print a message when it encounters errors
cron_output_error =
no
Save and close the
file.
How Do I Apply
Rebootless Kernel Updates?
You need to first
download and apply updates via RHN:
# yum -y update
OR
# yum update kernel
kernel-headers kernel-devel
Don't reboot the
box, simply type the following command to apply hotfix:
# uptrack-upgrade
To see a list of
updates that are currently installed, enter:
# uptrack-show -y
Sample Email
Notification
You will get an
email as follows when updates are available:
Fig.01: Ksplice
Update Notification
Fig.01: Ksplice
Update Notification
The web interface
also provides information about your server and installed kernel
updates:
Fig.02: Uptrack Web
Interface
Fig.02: Uptrack Web
Interface
Conclusion
The pricing is as
follows:
Monthly price per
system First 20 servers : $3.95
Beyond 20 servers:
$2.95
Currently it is free
for all Ubuntu users.
Ksplice is a pretty
good and stable software. This is useful for Linux admin or business
who can not accept downtime for patching. A few business comes in my
mind:
Small shop, say 8-12
Linux based servers.
Pro-blogging or
webmaster servers (a typical setup included one web server and one db
server). Avoiding downtime means more ad revenue for webmasters.
Hosting companies -
again avoiding downtime means good customer satisfactions and less
work for sys admins. If you run VM based hosting (OpenVZ or XEN based
vps) you can avoid downtime too.
Small cluster of
Linux system, say 6 system - If cluster is using 80% of capacity and
if one of node rebooted for kernel upgrade, load will up for rest of
5 systems. In such case, this service can help to keep load under
control without rebooting the box. However, this is NOT very useful
for very large Linux based cluster redundant load-balanced servers,
routers, switches, firewalls etc. Since your cluster is so large that
4-5 servers failing makes no difference to the remaining nodes. In
some cases it is possible to do geo load balancing too.
But I've HA Failover
Solution In Place...
100% uptime depends
upon lots of factors and and HA solution handles hardware or other
failures very well. However, Ksplice service is not all about 100%
uptime, it is about not rebooting your server for a Linux kernel
upgrade. You can easily combine Ksplice with HA solution (such as
keepalived+nginx reverse proxy) and try to get perfect five 9s. I
highly recommend this service for small to medium size business or
professional webmasters.
