Nov 27

CentOS 6.8 – Script creating a new demo user

By Czapski Michael Demo Building No Comments »

Introduction

Please see the article “Build a Linux-based Infrastructure Solution Demonstration Series” (https://blogs.czapski.id.au/2016/10/build-a-linux-based-infrastructure-solution-demonstration-series) for rationale, introduction and links to articles in this series.

From time to time I may need another user account, configured with the same tools and settings as the demo user which was used in the earlier articles and will continue to be used in the subsequent articles.

In this post I show how a new user can be created and configured using the scripts which were already developed and which are available for use.

Pre-Requisites

This article assumes that

  1. The work is done in the Virtual Box Machine Image created in accordance with the instructions in the blog article to be found at https://blogs.czapski.id.au/2016/10/configure-virtual-box-virtual-machine-and-install-centos-6-8-base-image.
  2. The user “demo” has sudo access without a password. If this is not the case use the command “su -” and provide the password instead of saying “sudo -i” in the set of commands below

The instructions should work in other RedHat 6-like OS’ and OS versions.

Discussion

Let’s assume that we need another user’s environment configured the same way as the demo user’s environment. We were creating configuration scripts in the following articles:

  1. CentOS 6.8 – Script Adding Top Panel Applets – GEyes, ShowDesktop and Gnome Monitor
  2. CentOS 6.8 – Script adding a new gnome-terminal profile
  3. CentOS 6.8 – Create desktop branding scripts and brand desktop

Since the scripts are already available we will, in this article, create a different user, log in as that user, and execute the scripts to set up the environment.

Add user

Assuming that we are logged in as the demo user, which we will be if the article series was followed in the order in which it was published, we have sudo access.

NewUsername=ademo2
sudo useradd -c "${NewUsername} User" -m ${NewUsername}

sudo passwd ${NewUsername} <<'EOF'
welcome1
welcome1
EOF

sudo usermod -G vboxsf ${NewUsername}

Verify that the account was created

sudo -i -u ademo2 ls -al

su ademo2
Password: welcome1

cd
ls -al

exit

Use gdmflexiserver to switch to user ademo2 by running the following command

gdmflexiserver

The Greeter is displayed

041_greeter

Click “Other…”, then enter ademo2 as username and welcome1 as password.

Notice that the login desktop does not have the top panel applets to which we got used to by now when using the demo login into which we are automatically logged in at boot.

Disable Screen Saver and inactivity timer

After a while of inactivity a screen saver will be run. Let’s disable this feature. Right-click on the desktop and choose “Open in Terminal”, then execute the command scripts:

/bin/bash -v /media/sf_distros/scripts/002_disable_screen_saver_and_delays.sh

Configure top panel applets and nautilus file browser

Assuming that we are logged in as user ademo2, let’s add the top panel applets and configure nautilus file browser. Right-click on the desktop and choose “Open in Terminal…”, then execute the command scripts:

# add applets to top panel - you will get "Operation not permitted" at the end but the script will complete what it needs to do
/bin/bash -v /media/sf_distros/scripts/005_add_applets_to_top_panel.sh

# Add standard launchers to top panel - first "fix" the script which has the demo user embedded
sed -i 's|/demo/|/${USER}/|' /media/sf_distros/scripts/007_add_standard_launchers_to_top_panel.sh
/bin/bash -v /media/sf_distros/scripts/007_add_standard_launchers_to_top_panel.sh

/bin/bash -v /media/sf_distros/scripts/008_configure_nautilus_file_browser.sh

Configure gnome-terminal profiles

Assuming that this user account will be used to do the same kinds of things that the dmeo use will, let’s add the gnome-terminal profiles that we added for the demo user

/bin/bash -v /media/sf_distros/scripts/010_make_profile_very_visible.sh
/bin/bash -v /media/sf_distros/scripts/011_make_profile_console_scrolling.sh

Brand the desktop

Let’s brand the desktop so that we know what is there. This, as you will undoubtedly realise, is done on per-user basis, and perhaps needs to be reconsidered. If additional software is installed by a different user, for example the root user, neither the demo user nor the ademo2 user will have this reflected in their branded desktop. Still, this is probably better than nothing and as long as the administrator updates the branding files and runs the branding script at appropriate times things should go well enough.

# copy desktop branding script to the local directory for execution
# only needs to be done the first time
cp -v /media/sf_distros/scripts/013_source_desktop_branding_script.sh ${HOME}/brand_desktop.sh

# create a rarely changing content
cat <<-'EODECK' > ${HOME}/copyright_and_credits.txt
Copyright © 2016, Michael Czapski
EODECK

# create "current state" content - only needs to be done the first time branding is done
oldVer="v0.0.0"
newVer="v1.1.0"
touch ${HOME}/branding_installed_software_${oldVer}.txt
cp ${HOME}/branding_installed_software_${oldVer}.txt ${HOME}/branding_installed_software_${newVer}.txt

idLabel="Installed and Configured CentOS 6.8"

# append to "current state" content
cat <<-EODECK >> ${HOME}/branding_installed_software_${newVer}.txt
${newVer}, $(date +%Y-%m-%d\ %H:%M)
${idLabel}
EODECK

# brand the desktop
annotationFile=${HOME}/branding_installed_software_${newVer}.txt
creditsFile=${HOME}/copyright_and_credits.txt
buildFile=${HOME}/build_date.txt

${HOME}/brand_desktop.sh "${idLabel}" "${annotationFile}" "${creditsFile}" "${newVer}"

Explore, then log out from ademo2 user and return to demo user

Tagged with: • • • • • • • • • • • • • • • • • • • • •
Nov 26

CentOS 6.8 – Create desktop branding scripts and brand desktop

By Czapski Michael Demo Building No Comments »

Introduction

Please see the article “Build a Linux-based Infrastructure Solution Demonstration Series” (https://blogs.czapski.id.au/2016/10/build-a-linux-based-infrastructure-solution-demonstration-series) for rationale, introduction and links to articles in this series.

As I work with the various demonstration images I find myself taking longish breaks between bouts of activity so I like to have a clear indication, right on the desktop, of what state the image is in. What software was installed, what tis the name of the checkpoint I reached so that I can look up the specific section in the installation document I build at the same time, and so that I can resume work where I left off.

In this post I walk through the method of “branding” the desktop with text which tells me that what is installed, what the checkpoint has been reached, what the host name is and what user is logged in. I will subsequently use this script to brand the desktop each time something significant is done to the image.

The image blow shows the desktop branded using the method described in this article.

040_branded_desktop

Pre-Requisites

This article assumes that

  1. The work is done in the Virtual Box Machine Image created in accordance with the instructions in the blog article to be found at https://blogs.czapski.id.au/2016/10/configure-virtual-box-virtual-machine-and-install-centos-6-8-base-image.

The instructions should work in other RedHat 6-like OS’ and OS versions and on platforms that use gnome-2 desktop.

Discussion

The branding method relies on the ability to change desktop background using gconftool-2 by providing a location of the image which to use, and on the fact that ImageMagc can be used to programmatically manipulate images by adding text and other graphical artefacts to existing images.

This capability is used to mark up an existing desktop image with text that reflects the username, host name, label designating the state the image is in and a list of software which was installed up to the point at which desktop was branded.

Update ImageMagic Security Profile

As shipped in CentOS 6.8 and Oracle Linux 6U8 at least, ImageMagic, which I use to manipulate desktop image I will use, has security restrictions which prevent it being use the way it needs to be used to accomplish what needs to be accomplished in this post. To allow the manipulation to be done one must replace the ImageMagic security policy file. We will develop a script, to be added to the bilk initial setup script set, in the next section.

Let’s create a script which will update the ImageMagic security profile so that we can watermark the desktop image with text we want to see on the desktop.

cat <<-'EODECK' > /media/sf_distros/scripts/012_update_imagemagic_security_profile.sh

# Save ImageMagic policy file
if [ ! -f /etc/ImageMagick/policy.xml_orig ]; then
    sudo cp -v /etc/ImageMagick/policy.xml /etc/ImageMagick/policy.xml_orig
fi

# Create replacement policy file
cat <<-'EOF' | sudo tee /etc/ImageMagick/policy.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE policymap [
<!ELEMENT policymap (policy)+>
<!ELEMENT policy (#PCDATA)>
<!ATTLIST policy domain (delegate|coder|filter|path|resource) #IMPLIED>
<!ATTLIST policy name CDATA #IMPLIED>
<!ATTLIST policy rights CDATA #IMPLIED>
<!ATTLIST policy pattern CDATA #IMPLIED>
<!ATTLIST policy value CDATA #IMPLIED>
]>
<!--
  Configure ImageMagick policies.

 Domains include system, delegate, coder, filter, path, or resource.
 Rights include none, read, write, and execute.  Use | to combine them,
  for example: "read | write" to permit read from, or write to, a path.
  Use a glob expression as a pattern.
  Suppose we do not want users to process MPEG video images:
    <policy domain="delegate" rights="none" pattern="mpeg:decode" />
  Here we do not want users reading images from HTTP:
    <policy domain="coder" rights="read | write" pattern="HTTP" />
  Lets prevent users from executing any image filters:
    <policy domain="filter" rights="none" pattern="*" />
  The /repository file system is restricted to read only.  We use a glob
  expression to match all paths that start with /repository:
    <policy domain="path" rights="read" pattern="/repository/*" />
  Let's prevent possible exploits by removing the right to use indirect reads.
    <policy domain="path" rights="none" pattern="@*" />
  Any large image is cached to disk rather than memory:
    <policy domain="resource" name="area" value="1gb"/>
  Note, resource policies are maximums for each instance of ImageMagick (e.g.
  policy memory limit 1GB, -limit 2GB exceeds policy maximum so memory limit
  is 1GB).
-->
<policymap>
  <!-- <policy domain="system" name="precision" value="6"/> -->
  <!-- <policy domain="resource" name="temporary-path" value="/tmp"/> -->
  <!-- <policy domain="resource" name="memory" value="2GiB"/> -->
  <!-- <policy domain="resource" name="map" value="4GiB"/> -->
  <!-- <policy domain="resource" name="area" value="1gb"/> -->
  <!-- <policy domain="resource" name="disk" value="16eb"/> -->
  <!-- <policy domain="resource" name="file" value="768"/> -->
  <!-- <policy domain="resource" name="thread" value="4"/> -->
  <!-- <policy domain="resource" name="throttle" value="0"/> -->
  <!-- <policy domain="resource" name="time" value="3600"/> -->
  <policy domain="coder" rights="read | write" pattern="EPHEMERAL" />
  <policy domain="coder" rights="read | write" pattern="HTTPS" />
  <policy domain="coder" rights="read | write" pattern="HTTP" />
  <policy domain="coder" rights="read | write" pattern="URL" />
  <policy domain="coder" rights="read | write" pattern="FTP" />
  <policy domain="coder" rights="read | write" pattern="MVG" />
  <policy domain="coder" rights="read | write" pattern="MSL" />
  <policy domain="coder" rights="read | write" pattern="TEXT" />
  <policy domain="coder" rights="read | write" pattern="LABEL" />
  <policy domain="coder" rights="read | write" pattern="TXT" />
<!--  <policy domain="path" rights="none" pattern="@*" /> -->
</policymap>
EOF
EODECK
chmod ug+x /media/sf_distros/scripts/012_update_imagemagic_security_profile.sh

Execute the script to update the policy file

/bin/bash -v /media/sf_distros/scripts/012_update_imagemagic_security_profile.sh

See the differences

diff -y --suppress-common-lines /etc/ImageMagick/policy.xml /etc/ImageMagick/policy.xml_orig

Create Desktop Branding script

Create the branding script with 4 arguments

cat <<-'EODECK' > /media/sf_distros/scripts/013_source_desktop_branding_script.sh
#!/bin/bash
# check that each individual argument exists
: ${1?"Usage: $0 " '${idLabel} ${annotationFile} ${creditsFile} ${newVer} - provide content for the idLabel - exiting ...'}
: ${2?"Usage: $0 " '${idLabel} ${annotationFile} ${creditsFile} ${newVer} - provide path to annotationFile - exiting ...'}
: ${3?"Usage: $0 " '${idLabel} ${annotationFile} ${creditsFile} ${newVer} - provide path to creditsFile - exiting ...'}
: ${4?"Usage: $0 " '${idLabel} ${annotationFile} ${creditsFile} ${newVer} - provide version number like 'v1.2.3' - exiting ...'}

idLabel=${1}
annotationFile=${2}
creditsFile=${3}
newVer=${4}

# "build date" is a date/tim stamp reflecting when the script was run
cat <<-EOF > ${HOME}/build_date.txt
Build: ${newVer}, $(date +%d\ %b\ %Y\ %H:%M)
EOF
buildFile=${HOME}/build_date.txt

# ImageMagic command uses the default.png background - this can be readily changes
# Username and Host name are written near the top right (northeast) in 42pt
# and near the bottom left (southwest) in 32pt
# content of the annotation file, credits file and build file are written in the appropriate
# places in the image - see pictire for where this is
#
mkdir -p ~/imgman
cd ~/imgman
bgfile=$(hostname -s)_${USER}.jpg
myhost=$(hostname)
convert /usr/share/backgrounds/default.png \
-gravity northeast -fill white -pointsize 42 \
-annotate +20+60 "${idLabel}\n${USER}\n${myhost}" \
-gravity southwest -fill white -pointsize 32 \
-annotate +20+40 "${myhost}\n${USER}\n${idLabel}" \
-gravity northwest -fill white -pointsize 18 \
-annotate +300+120 @${annotationFile} \
-gravity southwest -fill white -pointsize 14 \
-annotate +700+120 "$( cat ${creditsFile})" \
-gravity southwest -fill white -pointsize 14 \
-annotate +700+100 "$( cat ${buildFile})" \
${bgfile}

# replace the current desktop background with the modified desktop background
gconftool-2 -s -t string /desktop/gnome/background/picture_filename "${HOME}/imgman/${bgfile}"
EODECK
chmod ug+x /media/sf_distros/scripts/013_source_desktop_branding_script.sh

Copy desktop branding script to the local directory for use

cp -v /media/sf_distros/scripts/013_source_desktop_branding_script.sh ${HOME}/brand_desktop.sh

Brand the desktop

Create branding file with the content that rarely changes – it will appear at the centre near the bottom of the desktop

cat <<-'EODECK' > ${HOME}/copyright_and_credits.txt
Copyright © 2016, Michael Czapski
EODECK

It is expected that the software list file, which in my case contains the list of software I installed and configured, will grow between the times the desktop gets branded. To keep the list up to date one will copy the most recent version of the branding file with a new version and append text to it to provide information on what changed since.

Append to software list file – the first time around the software list file will not exist

oldVer="v0.0.0"
newVer="v1.1.0"
touch ${HOME}/branding_installed_software_${oldVer}.txt
cp ${HOME}/branding_installed_software_${oldVer}.txt ${HOME}/branding_installed_software_${newVer}.txt

Label is the text that identifies the current iteration of the image and in my case correlates with the checkpoint names in the installation document used to build the image and possibly with the snapshot names in VirtualBox .

idLabel="Installed and Configured CentOS 6.8"

The branding file incorporates the version, date/time stamp and the label

cat <<-EODECK >> ${HOME}/branding_installed_software_${newVer}.txt
${newVer}, $(date +%Y-%m-%d\ %H:%M)
${idLabel}
EODECK

Execute the script to brand the desktop

annotationFile=${HOME}/branding_installed_software_${newVer}.txt
creditsFile=${HOME}/copyright_and_credits.txt
buildFile=${HOME}/build_date.txt

${HOME}/brand_desktop.sh "${idLabel}" "${annotationFile}" "${creditsFile}" "${newVer}"

Add to initial bulk configuration script

It is expected that the image being configured a bit at a time in this series of articles will be created more than once for different purposes. With this assumptions the individual scripts are appended to a single script so that the second and subsequent images can be configured by a single script rather than having lots of scripts to execute manually.

Copy the global desktop branding script to the local directory for execution

Don’t actually execute this script while you are building the first image.

cat <<-'EODECK' >> /media/sf_distros/scripts/000_initial_bulk_configuration.sh
# update ImageMagic security policy file
/bin/bash -v /media/sf_distros/scripts/012_update_imagemagic_security_profile.sh

# copy desktop branding script to the local directory for execution
cp -v /media/sf_distros/scripts/013_source_desktop_branding_script.sh ${HOME}/brand_desktop.sh

EODECK
chmod ug+x /media/sf_distros/scripts/000_initial_bulk_configuration.sh
Tagged with: • • • • • • • • • • • • • • • • • •
Nov 20

CentOS 6.8 – Script adding a new gnome-terminal profile

By Czapski Michael Demo Building No Comments »

Introduction

Please see the article “Build a Linux-based Infrastructure Solution Demonstration Series” (https://blogs.czapski.id.au/2016/10/build-a-linux-based-infrastructure-solution-demonstration-series) for rationale, introduction and links to articles in this series.

As I work with the various demonstration images I find myself using gnome-terminal profiles configured to display server logs, scripting interactions and other kinds of stuff using different font sizes, terminal backgrounds and application exit behaviours. I used to configure these manually in each image, then dumping configured profiles into a xml file and loading them into a new image. The gnome-terminal dumps are quite large so this is somewhat cumbersome.

In this post I walk through the method of script-driven addition of gnome terminal profiles and gconftool-2-based configuration so that all of this can be scripted and can avoid the need to do it manually.

Pre-Requisites

This article assumes that

  1. The work is done in the Virtual Box Machine Image created in accordance with the instructions in the blog article to be found at https://blogs.czapski.id.au/2016/10/configure-virtual-box-virtual-machine-and-install-centos-6-8-base-image.

The instructions should work in other RedHat 6-like OS’ and OS versions and on platforms that use gnome-2 desktop.

Discussion

A gnome-terminal profile can be created manually. Just start a gnome-terminal, pull down the Edit menu, choose Profiles and Add new profile. Creating a new profile programmatically is harder.

The following commands will find out what is the “last” profile and will work out what the internal name of the new profile needs to be, then will clone the Default profile and use it to create a new profile, with the new internal and visible names, ready for gconftool-2 configuration.

If you execute these commands you will create a profile.

In the next section you will create scripts which combine all of these commands so that a profile can be created using a single script.

By exporting and manipulating the gnome-terminal global profile list we will determine the name of the “last” profile. This name will either be “Default”, if there is only one, the default profile, or a name of the form “ProfileX”, where X will be 0, 1, 2, …, depending on the number of profiles, in addition to the “Default” profiles, which are configured.

The profile list will look like [Default], or [Default,Profile0], i.e. there will be square brackets surrounding the comma-separated list of names. The sed command will strip the square brackets so that we get just the comma-separated list of names.

profiles_list=$(gconftool-2 --get "/apps/gnome-terminal/global/profile_list" | sed "s|\[||;s|\]||;")
echo "1 Profiles List: " ${profiles_list}

Let’s take the list of profile names, “Default” or “Default,Profile0,Provile1”, etc.. and remove all elements from the list up to and including the last comma. This will leave either the last profile name of the form “ProfileX” or the literal “Default”

last_profile=$(echo "${profiles_list}" | sed "s/^.*,//" | sed 's/Profile//')
echo "Last Profile Name/Number: " ${last_profile}

If the last_profile is the literal “Default” then the “next” internal profile name will be “Profile0” otherwise it will be Profile(X + 1) -> is 2 then Profile3, etc.

Let’s set the “ProfileX” X number to 0 if only default is there or whatever the last is plus 1

if [ ${last_profile} == "Default" ]; then
    next_profile_number=0;
    echo "1 New Profile Number: " ${next_profile_number}
else
    next_profile_number=$(( ${last_profile} + 1 ));
    echo "2 New Profile Number: " ${next_profile_number}
fi
echo "New Profile Number: " ${next_profile_number}

We need to tell gnome that the list of profile names is different. If it was “Default,Profile0” then with the new profile it needs to be “Default,Profile0,Profile1”

Let’s construct profiles list with extra profile “number”

profiles_list=$(echo "[${profiles_list},Profile${next_profile_number}]")
echo "1 Profiles List: " ${profiles_list}

By now we established the new internal profile name – Profile0 or Profile1 or …

Let’s set the new visible profile name as an environment variable for ease of use later

profileName=MyNewProfile

Let’s get a dump of the default profile. We will use it as a template for the new profile

gconftool-2 --dump "/apps/gnome-terminal/profiles/Default" > /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

Let’s change global name to the new internal profile name in the Default profile dump

sed -i “s|Default|Profile${next_profile_number}|g” /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

Let’s load the new profile – it will not be useable until the next step is executed

gconftool-2 --load /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

Let’s tell gnome-terminal that is has another profile by updating the profile_list property

gconftool-2 --set --type list --list-type string "/apps/gnome-terminal/global/profile_list" "${profiles_list}"

Let’s change the visible_name property to the “friendly” name we want to see in the Profiles dropdown

gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/visible_name "${profileName}"

Let’s set other properties to suit

gconftool-2 --set --type boolean /apps/gnome-terminal/profiles/Profile${next_profile_number}/use_system_font "false"
gconftool-2 --set --type boolean /apps/gnome-terminal/profiles/Profile${next_profile_number}/use_theme_colors "false"
gconftool-2 --set --type boolean /apps/gnome-terminal/profiles/Profile${next_profile_number}/login_shell "true"
gconftool-2 --set --type boolean /apps/gnome-terminal/profiles/Profile${next_profile_number}/default_show_menubar "false"
gconftool-2 --set --type boolean /apps/gnome-terminal/profiles/Profile${next_profile_number}/scrollback_unlimited "true"
gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/exit_action "hold"
gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/font "Monospace 14"
gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/background_color "#FFFFFFFFDDDD"
gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/foreground_color "#0000FFFF0000"
gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/scrollbar_position "hidden"

Let’s create a terminal using the profile we just created

gnome-terminal --geometry=80x24+0+0 --profile=${profileName} title "${profileName}" --zoom 0.8 -e "/bin/sh"

The steps above helped us create and configure a new gnome-terminal profile and create a terminal which is using that profile.

Design the “create new gnome-terminal profile” script

cat <<-'EODECK' > /media/sf_distros/scripts/create_new_gnome-terminal_profile.sh
#!/bin/bash
# The following script will find out what is the "last" profile and will work out
# what the internal name of the new profile needs to be, then will clone the Default profile
# and use it to create a new profile, with the new internal and visible names,
# ready for gconftool-2 configuration.

# Let's set the new visible profile name as an environment variable
# for ease of use later

profileName=${1?"Usage: $0 profileName # please provide value for the visible_name profile property - make sure that it is a valid string identifier, i.e consisting of letters and digits only"}

# By exporting and manipulating the gnome-terminal global profile list we will determine
# the name of the "last" profile. This name will either be "Default", if there is only one,
# the default profile, or a name of the form "ProfileX", where X will be 0, 1, 2, …,
# depending on the number of profiles, in addition to the "Default" profiles,
# which are configured.

profiles_list=$(gconftool-2 --get "/apps/gnome-terminal/global/profile_list" | sed "s|\[||;s|\]||;")
echo "1 Profiles List: " ${profiles_list}

# Let's take the list of profile names, "Default" or "Default,Profile0,Provile1", etc..
# and remove all elements from the list up to and including the last comma.
# This will leave either the last profile name of the form "ProfileX" or the literal "Default"

last_profile=$(echo "${profiles_list}" | sed "s/^.*,//" | sed 's/Profile//')
echo "Last Profile Name/Number: " ${last_profile}

# If the last_profile is the literal "Default" then the "next" internal profile name
# will be "Profile0" otherwise it will be Profile(X + 1) -> is 2 then Profile3, etc.
# Let's set the "ProfileX" X number to 0 if only default is there or whatever the last is
# plus 1

if [ ${last_profile} == "Default" ]; then
    next_profile_number=0;
    echo "1 New Profile Number: " ${next_profile_number}
else
    next_profile_number=$(( ${last_profile} + 1 ));
    echo "2 New Profile Number: " ${next_profile_number}
fi
echo "New Profile Number: " ${next_profile_number}

# We need to tell gnome that the list of profile names is different.
# If it was "Default,Profile0" then with the new profile
# it needs to be "Default,Profile0,Profile1"
# Let's construct profiles list with extra profile "number"

profiles_list=$(echo "[${profiles_list},Profile${next_profile_number}]")
echo "1 Profiles List: " ${profiles_list}

# By now we established the new internal profile name - Profile0 or Profile1 or ...

# Let's get a dump of the default profile. We will use it as a template for the new profile

gconftool-2 --dump "/apps/gnome-terminal/profiles/Default" > /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

# Let's change global name to the new internal profile name in the Default profile dump

sed -i "s|Default|Profile${next_profile_number}|g" /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

# Let's load the new profile - it will not be useable until the next step is executed

gconftool-2 --load /tmp/${USER}_gnome-terminal_profiles_${profileName}.xml

# Let's tell gnome-terminal that is has another profile by updating the profile_list property

gconftool-2 --set --type list --list-type string "/apps/gnome-terminal/global/profile_list" "${profiles_list}"

# Let's change the visible_name property to the "friendly" name we want to see
# in the Profiles dropdown

gconftool-2 --set --type string /apps/gnome-terminal/profiles/Profile${next_profile_number}/visible_name "${profileName}"

EODECK
chmod ug+x /media/sf_distros/scripts/create_new_gnome-terminal_profile.sh

The following script, given the name of the profile, the data type fo the property to change, the name of the property to change and the value to which to change the property will make the change

cat <<-'EODECK' > /media/sf_distros/scripts/set_profile_property.sh
#!/bin/bash

profileName=${1?"Usage: $0 profileName keyName keyType keyValue # please provide value of the visible_name of the profile whose property you want to change"}
keyName=${2?"Usage: $0 profileName keyName keyType keyValue # please provide name of the profile key which you want to change"}
keyType=${3?"Usage: $0 profileName keyName keyType keyValue # please provide data type of the profile key which you want to change - boolean, string are supported - lists are not"}
keyValue=${4?"Usage: $0 profileName keyName keyType keyValue # please provide value of the profile key which you want to change"}

profileNum=$(gconftool-2 --search-key visible_name | grep ${profileName} | tail -n 1 | sed 's|^.*/Profile||;s|/.*$||')
echo "ProfileNum: " ${profileNum}

gconftool-2 --set --type ${keyType} /apps/gnome-terminal/profiles/Profile${profileNum}/${keyName} "${keyValue}"
EODECK
chmod ug+x /media/sf_distros/scripts/set_profile_property.sh

Create scripts for new profiles very_visble and console_scrolling

The very_visible profile will have larger font (Monospace, 14) and a green background, to distinguish the very_visible terminal from a “regular” gnome-terminal.

cat <<-'EODECK' > /media/sf_distros/scripts/010_make_profile_very_visible.sh
#!/bin/bash
/media/sf_distros/scripts/create_new_gnome-terminal_profile.sh very_visible

/media/sf_distros/scripts/set_profile_property.sh very_visible use_system_font boolean false
/media/sf_distros/scripts/set_profile_property.sh very_visible use_theme_colors boolean false
/media/sf_distros/scripts/set_profile_property.sh very_visible login_shell boolean true
/media/sf_distros/scripts/set_profile_property.sh very_visible default_show_menubar boolean false
/media/sf_distros/scripts/set_profile_property.sh very_visible scrollback_unlimited boolean true
/media/sf_distros/scripts/set_profile_property.sh very_visible exit_action string hold
/media/sf_distros/scripts/set_profile_property.sh very_visible font string "Monospace 14"
/media/sf_distros/scripts/set_profile_property.sh very_visible background_color string "#FFFFFFFFDDDD"
/media/sf_distros/scripts/set_profile_property.sh very_visible foreground_color string "#000000000000"
/media/sf_distros/scripts/set_profile_property.sh very_visible scrollbar_position string hidden
EODECK
chmod ug+x /media/sf_distros/scripts/010_make_profile_very_visible.sh

 

The console_scrolling profile will have larger font (Monospace, 9) and a black background, to distinguish the console_scrolling terminal from a “regular” gnome-terminal.

cat <<-'EODECK' > /media/sf_distros/scripts/011_make_profile_console_scrolling.sh
#!/bin/bash
/media/sf_distros/scripts/create_new_gnome-terminal_profile.sh console_scrolling

/media/sf_distros/scripts/set_profile_property.sh console_scrolling use_system_font boolean false
/media/sf_distros/scripts/set_profile_property.sh console_scrolling use_theme_colors boolean false
/media/sf_distros/scripts/set_profile_property.sh console_scrolling login_shell boolean true
/media/sf_distros/scripts/set_profile_property.sh console_scrolling default_show_menubar boolean false
/media/sf_distros/scripts/set_profile_property.sh console_scrolling scrollback_unlimited boolean true
/media/sf_distros/scripts/set_profile_property.sh console_scrolling scroll_on_output boolean true
/media/sf_distros/scripts/set_profile_property.sh console_scrolling exit_action string hold
/media/sf_distros/scripts/set_profile_property.sh console_scrolling font string "Monospace 9"
/media/sf_distros/scripts/set_profile_property.sh console_scrolling background_color string "#000000000000"
/media/sf_distros/scripts/set_profile_property.sh console_scrolling foreground_color string "#FFFFFFFFFFFF"
/media/sf_distros/scripts/set_profile_property.sh console_scrolling scrollbar_position string hidden
EODECK
chmod ug+x /media/sf_distros/scripts/011_make_profile_console_scrolling.sh

Execute commands to create and configure the two profiles

/bin/bash -v /media/sf_distros/scripts/010_make_profile_very_visible.sh
/bin/bash -v /media/sf_distros/scripts/011_make_profile_console_scrolling.sh

Add to initial bulk configuration script

It is expected that the image being configured a bit at a time in this series of articles will be created more than once for different purposes. With this assumptions the individual scripts are appended to a single script so that the second and subsequent images can be configured by a single script rather than having lots of scripts to execute manually.

Append “create gnome-terminal profiles” script execution commands to the initial bulk configuration script. This script is intended to collect all automated configuration commands and scripts so that they can be all executed in one go on a brand new image if one gets to do this the second and subsequent times.

Don’t actually execute this script while you are building the first image.

cat <<-'EODECK' >> /media/sf_distros/scripts/000_initial_bulk_configuration.sh
# create very_visible gnome-terminal profile
/bin/bash -v /media/sf_distros/scripts/010_make_profile_very_visible.sh

# create console_scrolling gnome-terminal profile
/bin/bash -v /media/sf_distros/scripts/011_make_profile_console_scrolling.sh

EODECK
chmod ug+x /media/sf_distros/scripts/000_initial_bulk_configuration.sh
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Nov 05

CentOS 6.8 – Update DHCP address in /etc/hosts at boot

By Czapski Michael Demo Building No Comments »

Introduction

Please see the article “Build a Linux-based Infrastructure Solution Demonstration Series” (https://blogs.czapski.id.au/2016/10/build-a-linux-based-infrastructure-solution-demonstration-series) for rationale, introduction and links to articles in this series.

As I work with the various demonstration images I find myself using the same tools, I naturally expect the tools to be ready to hand so I find myself adding the same launchers to the top panel.

In this article I build and execute a script which will add the “Update DHCP address in /etc/hosts at boot” script to the interactive boot level startup sequence so that the ip address is updated at boot to reflect the host ip address assigned to the host by DHCP. As in previous blog articles I also add the new scripts to the “initial configuration” script which is built cumulatively in the various articles in this series.

Pre-Requisites

This article assumes that

  1. The work is done in the Virtual Box Machine Image created in accordance with the instructions in the blog article to be found at https://blogs.czapski.id.au/2016/10/configure-virtual-box-virtual-machine-and-install-centos-6-8-base-image.
  2. The user “demo” has sudo access without a password. If this is not the case use the command “su -” and provide the password instead of saying “sudo -i” in the set of commands below

The instructions should work in other RedHat 6-like OS’ and OS versions.

Discussion

In the demonstration image as configured so far, there is no reference to the demo.demodomain.org in the /etc/hosts file.

We could manually update the /etc/hosts and point the demo.demodomain.org to 120.0.0.1, the loopback address. If it matters that the demo.demodomain.org points to an actual IP address of the NAT interface which a DHCP server assigns, and may change at different times or on different networks, we are better off creating a script to set /etc/hosts at boot so that the correct IP address is embedded. Everything that wants to translate the host name to the IP address uses /etc/hosts.

The /etc/hosts in the image, as at now, looks like this:

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Let’s explore how this hosts file can be “fixed” to configure the “real” IP address of the host at boot time.

Before making changes to the /etc/hosts file lets save it so we can restore it if things go wrong.

sudo cp /etc/hosts /etc/hosts_as_installed

Let’s append the 127.0.0.1 address to /etc/hosts – it will be replaced by the script we are going to create shortly.

cat <<-'EOF' | sudo tee --append /etc/hosts
127.0.0.1   demo.demodomain.org
EOF

Add boot-time script to insert the current DHCP host IP and associate it with the host name

cat <<-'EOF' | sudo tee /etc/init.d/ofixhostip
#!/bin/bash
ipaddr=$(/sbin/ifconfig eth0| grep 'inet addr' | cut -d: -f2 | awk '{print $1}')
hn=$(hostname -s)
hnd=$(hostname)
sed -i '$s/.*/'$ipaddr'  '$hnd'   '$hn'/' /etc/hosts
EOF
sudo chmod ug+x /etc/init.d/ofixhostip

Add to interactive boot level (5) sequence

sudo /bin/sh -c "cd /etc/rc5.d; ln -s ../init.d/ofixhostip S10ofixhostip"

Reboot

sudo reboot

Verify IP address in /etc/hosts

cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.2.15  demo.demodomain.org   demo

Restore after changes to the /etc/hosts file so that we can test the script we will be developing

sudo cp -v /etc/hosts_as_installed /etc/hosts

Implementation

Now that we understand what needs to be done, and know how to do it, let’s create a script that will automate this part of image configuration for the next time we are creating a new image that needs this functionality.

Create the configuration script

mkdir -p /media/sf_distros/scripts
cat <<-'EODECK' > /media/sf_distros/scripts/009_update_dhcp_address_at_boot.sh
#!/bin/bash
# add replacement placeholder
cat <<-'EOF' | sudo tee --append /etc/hosts
127.0.0.1   demo.demodomain.org
EOF

# Add boot-time script to insert the current DHCP host IP and associate it with the host name
cat <<-'EOF' | sudo tee /etc/init.d/ofixhostip
#!/bin/bash
ipaddr=$(/sbin/ifconfig eth0| grep 'inet addr' | cut -d: -f2 | awk '{print $1}')
hn=$(hostname -s)
hnd=$(hostname)
sed -i '$s/.*/'$ipaddr'  '$hnd'   '$hn'/' /etc/hosts
EOF
sudo chmod ug+x /etc/init.d/ofixhostip

# Add to interactive boot level (5) sequence
sudo /bin/sh -c "cd /etc/rc5.d; ln -f -s ../init.d/ofixhostip S10ofixhostip"

EODECK
chmod ug+x /media/sf_distros/scripts/009_update_dhcp_address_at_boot.sh

Execute the script

/bin/bash -v /media/sf_distros/scripts/009_update_dhcp_address_at_boot.sh

Reboot

sudo reboot

Verify IP address in /etc/hosts

cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.2.15  demo.demodomain.org   demo

It is expected that the image being configured a bit at a time in this series of articles will be created more than once for different purposes. With this assumptions the individual scripts are appended to a single script so that the second and subsequent images can be configured by a single script rather than having lots of scripts to execute manually.

Append “Update DHCP address in /etc/hosts at boot” script execution commands to the initial bulk configuration script. This script is intended to collect all automated configuration commands and scripts so that they can be all executed in one go on a brand new image if one gets to do this the second and subsequent times.

Don’t actually execute this script while you are building the first image.

cat <<-'EODECK' >> /media/sf_distros/scripts/000_initial_bulk_configuration.sh
# Update DHCP address in /etc/hosts at boot
/bin/bash -v /media/sf_distros/scripts/009_update_dhcp_address_at_boot.sh

EODECK
chmod ug+x /media/sf_distros/scripts/000_initial_bulk_configuration.sh
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