Diskless image configuration - manual setup
This article explains how to setup MANUALLY a netboot image.
Instead of manual operations you can use some config managers such as Puppet or Chef.
- 1 Get distribution's content
- 2 Access distribution
- 3 Setup
- 3.1 Adjust default login/password
- 3.2 Update sources.list and install key packages
- 3.3 Kernel libraries
- 3.4 Samba client
- 3.5 Smartcard drivers
- 3.6 Adjust bash and vim configuration
- 3.7 Edit mount points (/etc/fstab)
- 3.8 Firewall script
- 3.9 Setup network interfaces
- 3.10 Clear hostname
- 3.11 Setup correct DNS
- 3.12 Keyboard configuration
- 3.13 Monitoring client
- 4 Exit client distro
- 5 NFS virtual machine update
- 6 Optional: XFCE frontend
Get distribution's content
This step must be perform on the NFS server with a privileged user.
cd /nfs/wheezy debootstrap wheezy /nfs/wheezy
cd /nfs/trusty debootstrap trusty /nfs/trusty
If you try to update a virtual machine then you should do the following step: Diskless image configuration - manual setup#Set resolv.conf
This step must be perform on the NFS server with a privileged user. You'll "mount" the NFS client system, then all commands will only affect the NFS client until you run "exit".
# Debian 7.x chroot /nfs/wheezy/ # Ubuntu 14.04 chroot /nfs/trusty/
From here you can perform operation as if you were on a separate machine.
Only the current distribution (= the client one) will be affected.
Adjust default login/password
First of all, you have to create / adjust the default user.
# Add new user adduser <username> # Add user to sudoers group usermod -a -G sudo <username>
Now you can use that user:
su <username> sudo -s
You can check that you really are in the "Virtual machine" by checking "/srv/". It should be empty !
- Note -
On Debian distribution you have to install "sudo" manually. It's not in the defaults packages.
Update sources.list and install key packages
Your client need to have some key packages in order to work. Without these package even the NetBoot will fail !!
First of all: edit your sources.list
apt-get install vim nano vim /etc/apt/sources.list
Put the following:
### Custom repositories list # # May 2014 - Guillaume Diaz # This is an ajdustement of the default "debootstrap" sources.list # This is required to provided update, security and advanced tools to all our clients # ######################### # Debian 7.x [Wheezy] ######################### deb http://ftp.se.debian.org/debian stable main contrib deb http://ftp.debian.org/debian/ wheezy-updates main contrib deb http://security.debian.org/ wheezy/updates main contrib ######################### # Ubuntu 14.04 LTS [Trusty] ######################### # Official repositories deb http://se.archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse deb http://se.archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse deb http://security.ubuntu.com/ubuntu trusty-security main restricted universe multiverse # Official updates deb http://se.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse # Canonical partners #deb http://archive.canonical.com/ubuntu trusty partner # Community partners #deb http://extras.ubuntu.com/ubuntu trusty main
Update your package list:
apt-get update && apt-get upgrade
Now, you can install the basic programs:
# NFS client. This is ABSOLUTELY MANDATORY ! That's the only way to mount the /root apt-get install nfs-common apt-get install initramfs-tools # IPTABLES. This is ABSOLUTELY MANDATORY ! apt-get install iptables # NFS is a bit low, and if you're using many client it might result in time faults. # You must install NTP to overcome this !! apt-get install ntp ntpdate # Basic set of utilities apt-get install unzip zip apt-get install htop apt-get install python3 apt-get install sysv-rc-conf # Network tools apt-get install curl # Advanced APT manager (require to add repository from command line) apt-get install software-properties-common python-software-properties # SSH server apt-get install openssh-server openssh-client # Midnight commander apt-get install mc # JAVA (that is required for my application) # Depending on your target usage you might not need it. # !!! Careful !!! Java + its dependencies will take about 350 Mo !!! ##### Ubuntu repository add-apt-repository ppa:webupd8team/java ##### Debian repository echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee -a /etc/apt/sources.list apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886 ##### Installation apt-get update && apt-get upgrade apt-get install oracle-java7-installer
You need to download the kernel libraries and modules in order to run correctly all the services. This is very important, otherwise your diskless client will have problems.
Get your current kernel version:
Then install the corresponding kernel files:
# you can check the list of available packages apt-cache search linux-image # put your kernel version like '22.214.171.124-generic' apt-get install --reinstall linux-image-...
If asked: do NOT install GRUB.
You might encounter some errors during installation since you're not running the kernel... No panic ! :-)
apt-get install -f
Since SAMBA is a better file-sharing system than NFS it's a good idea to install it!
Actually, this is how we access our common files. We do NOT rely on NFS for the shared files.
apt-get install samba smbclient cifs-utils
Then you can check if the service is working (or not)
If you see some error message, then please see #Kernel_libraries
Only install the smartcards driver if:
- Your NFS server has already these driver installed
- The kernel you're gonna used support these drivers
# Smart-card drivers apt-get install libpcsclite1 pcscd pcsc-tools
For the smart-card drivers you can see Drivers#Smart-card_drivers
Adjust bash and vim configuration
Edit your VIM configuration:
Enable dark background + set nu + set ruler
Edit your bash configuration files to adjust the alias and enable auto-completion:
vim /etc/bash.bashrc vim /home/<username>/.bashrc vim /root/.bashrc
Edit mount points (/etc/fstab)
Create mount point for the common files:
mkdir -p /nfs/common chmod -R 777 /nfs/common
You must edit the mount points to get the client working!
# /etc/fstab: static file system information. # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc defaults 0 0 /dev/nfs / nfs defaults,ro,noatime 1 1 ### Common NFS share. # It's better to use SAMBA if you can. #172.16.50.2:/nfs/common /nfs/common nfs defaults,rw,noatime 0 0 #### ### Samba file-share //smartcard-gw/file-share /nfs/common cifs guest,uid=1000,iocharset=utf8 0 0 none /tmp tmpfs defaults,rw,noexec,nosuid,size=512M 0 0 none /var/run tmpfs defaults,rw,noatime,noexec,nosuid 0 0 none /var/lock tmpfs defaults,rw,noatime,noexec,nosuid 0 0 none /var/tmp tmpfs defaults,rw,noexec,nosuid,size=128M 0 0 none /var/log tmpfs defaults,rw,noexec,nosuid,size=128M 0 0 none /run/shm tmpfs nodev,nosuid,noexec,size=256M 0 0
- Reminder -
For the 2 Go constraints you can adjust some size arguments or even remove them: it will be delegate to the NetBoot client and automatically handled.
- Notes -
- There is no swap as the /tmp is already a RAMdisk and that should be enough.
- Notice the "none" + "tmpfs" for all mount point except the root "/" and "proc"
- ro - For Read Only mount point
- noatime - To speed up things by skipping the file access time registration. That will skip some write operations but it make it harder to know what has been accessed when. That's perfect for /tmp but it should not be set anywhere else.
- realtime - only update file timestamp if the file or directory has been modified since the last atime update. You might choose to use ‘noatime’ on most of your filesystems but leave /var/spool and /tmp as ‘relatime’:
- noexec - To prevent people from running executables in /tmp. Some rootkits do that. This flag might cause trouble for some legitimate applications so be sure to test everything properly after setting this flag.
- nosuid - To prevent the setuid bit from being set on files in /tmp.
- no size on "/var/run" and "/var/lock" : it's better to let the system managed that
As "/var/tmp" is used to preserve temporary data across reboot - and due to the fact that it's a temp RAMdisk - it should not be used! However, to prevent bugs it's safer to allow some little space.
Beware "/var/log" will be reset at each reboot! So you absolutely need to setup some kind of central log solution - using logstash for instance.
For the Samba file-share properties you can check the following article: https://wiki.ubuntu.com/MountWindowsSharesPermanently
Download, adjust and copy the following FW script to your clients: http://www.daxiongmao.eu/wiki_upload_files/firewall/firewall-nfs-client.sh
See Firewall to get more details.
Setup network interfaces
Even though you're using the NetBoot process you still have to register some interfaces! More important, the NetBoot disable the loopback "lo" - so you should better add that one back!
# Adjust "xxxx" by your distribution name vim /etc/network/interfaces
auto lo iface lo inet loopback # Ethernet default interface auto eth0 iface eth0 inet dhcp # Intel NUC ethernet interface is named em1 auto em1 iface em1 inet dhcp
Even though you're using a NetBoot configuration you need to tell the client to use DHCP and retrieve its network settings (DNS, IP, GW, ...) dynamically. That's why you have to enable your ethernet interface.
By default your client will have the same hostname as the server due to the "deboostrap" installation. :(
You MUST clean that in order to retrieve the name from your DNS.
That file must be empty.
Setup correct DNS
Your network configuration might change in the future, therefore you don't want to save any hard DNS reference in the client!
You have to edit resolv.conf configuration and make it clean.
Both following files should be empty - if not then you have to clean them !
You can also clean the resolv.conf that was generated by deboostrap:
You can delete all DNS references from that file.
You have to set your keyboard configuration to use something else than the US layout as default.
Adjust the lang and keyboard size:
XKBMODEL="pc105" XKBLAYOUT="se" XKBVARIANT="" XKBOPTIONS=""
Now you can run the configuration utility:
I'm using Zabbix as a monitoring solution. See Zabbix agent setup.
I also advise you to install a SNMP client.
Exit client distro
Update status cleaning
If you've been updating the virtual machine, don't forget to clean your mess ! see #Clean resolv.conf
Exit virtual machine
Exit until your reach your starting point.
NFS virtual machine update
Before chrooting, from the NFS server, you need to reset the "/etc/resolv.conf":
echo /etc/resolv.conf > /nfs/trust/etc/resolv.conf
Where "/nfs/trusty/" is the name of the target virtual machine.
Now you can CHROOT and use APT-GET or any other applications.
Before leaving don't forget to clean the resolv.conf !
echo "" > /etc/resolv.conf
Optional: XFCE frontend
If you'd like to setup a graphical environment as a rescue | alternative, then I recommend you XFCE :)
apt-get install --no-install-recommends xubuntu-desktop apt-get install xfce4 xubuntu-icon-theme xubuntu-default-settings apt-get install xfce4-terminal xfce4-taskmanager libxfce4ui-utils thunar ## It's always useful to have a default Internet browser apt-get install firefox ## Text editors apt-get install mousepad ## Screenshot application - very useful to produce nice documentation apt-get install xfce4-screenshooter xfce4-screenshooter-plugin ## You should also install guake - that's pretty useful too ! apt-get install guake
This will install XFCE without the default - none required - Ubuntu applications.
>> You still need about 430 Mo, but that's the minimal setup.
How to setup XFCE for NetBoot use?
You have to mount the XFCE in read / write mode for configuration.
- Adjust your NFS configuration in "/etc/exports" + reload NFS server
- Adjust your client "/etc/fstab"
Boot on your Xubuntu O.S and setup it as you like it to be :)
- Add desktop launchers
- Update the panel to add the "applications menu" + "show desktop"
Then, once everything is setup you must reboot to ensure your settings are correct!
XFCE doesn't work in read-only mode!! ... At least I didn't managed to achieve that.
So, you MUST let the image in RW mode to NetBoot on it. As a result, you might encounter some concurrency issues if many users are logged at the same time.