While these cameras are normally very stable (no lock-ups for weeks or months at a time) it still happens. To make things work more smoothly, I decided to find a way to restart the devices with cron.

I decided to have the cameras be reset twice a month (on the 1st and 15th of each month at 4am).


crontab -e

0 4 1,15 * * wget --http-user=admin --http-password=YOUR-PASSWORD -O /dev/null --post-data="Reset= Yes " http://camera1/Reply.html

You can remove the –http-user and –http-password sections if you do not have an admin user/password set.

This article assumes you’ve already downloaded the iso and have a working PXE boot server.

First, copy the contents of the iso to a directory we can work with


mkdir /tmp/910

mount -o loop ubuntu-9.10-desktop-i386.iso /tmp/910

cp -r /tmp/910 /tftpboot


Convert initrd.lz to initrd.gz


cd /tftpboot/910/casper

mkdir initrd

cp initrd.lz initrd

cd initrd

lzma -dc -S .lz initrd.lz | cpio -id

rm initrd.lz

find . | cpio --quiet --dereference -o -H newc | gzip -9 > initrd.gz

cp initrd.gz /tftpboot/910/casper


Now add the appropriate lines to pxelinux (Example: /tftpboot/pxelinux.cfg/default)


LABEL Ubuntu 9.10 i386 Unmodified Livecd
KERNEL 910/casper/vmlinuz
APPEND root=/dev/nfs boot=casper netboot=nfs nfsroot=192.168.0.1:/home/tftpboot/910 initrd=910/casper/initrd.gz quiet splash --


Make sure /tftpboot is shared via nfs; in /etc/exports add the following line


/tftpboot/910 192.168.0.0/24(rw,async,no_subtree_check)


Reload the NFS server

/etc/init.d/nfs-kernel-server reload

The following is one line

ldapclient manual -a credentialLevel=proxy -a authenticationMethod=simple -a proxyDN=cn=admin,dc=server -a proxyPassword=yourpassword -a defaultSearchBase=dc=server -a defaultServerList=192.168.1.1:389 -a serviceSearchDescriptor=passwd:ou=People,dc=server -a
serviceSearchDescriptor=group:ou=Groups,dc=server

Add the following lines to their appropriate sections in /etc/pam.conf

login   auth required           pam_ldap.so.1
other   auth required           pam_ldap.so.1
passwd  auth required         pam_ldap.so.1

Test LDAP with

ldaplist -l passwd

Test user authentication using the following steps

mkdir /export/home/ldapuser

chown ldapuser /export/home/ldapuser

Edit /etc/auto_home and add the following BEFORE “+auto_home”

ldapuser localhost:/export/home/ldapuser

SSH to test

ssh ldapuser@localhost

You should be in! If not, you may have to change the following in /etc/ssh/sshd_config

PAMAuthenticationViaKBDInt no

#Change from yes to no

Restart SSH

svcadm restart ssh

If you are still unable to log in, your userPassword attribute probably needs to be changed from md5/md5crypt to crypt.

su – ldapuser

passwd

After changing your password you should be able to log in.

apt-get install sysstat

# iostat -m
Linux 2.6.27-14-generic (slowaris)      07/28/2009      _x86_64_

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
4.88    6.65    3.03    1.49    0.00   83.95

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn

md0             221.24         0.64         0.78    1765002    2159490

We can see that I/O isn’t terribly high here, but there are 221 transfers per second going on.

To check what processes are causing I/O

echo 1 > /proc/sys/vm/block_dump

tail -f /var/log/syslog | grep md0

Jul 28 08:20:12 server kernel: [2752582.434647] kvm(17362): READ block 1017744552 on md0
Jul 28 08:20:12 server kernel: [2752582.502401] kvm(17362): READ block 615283608 on md0
Jul 28 08:20:13 server kernel: [2752582.634622] kvm(17362): READ block 1017744576 on md0
Jul 28 08:20:14 server kernel: [2752583.964709] kvm(17362): READ block 1017744608 on md0
Jul 28 08:20:14 server kernel: [2752584.372889] kvm(1868): dirtied inode 17367041 (live-default-32.img) on md0
Jul 28 08:20:14 server kernel: [2752584.372908] kvm(1868): dirtied inode 17367041 (live-default-32.img) on md0

We see that kvm is causing some disk I/O; now where know where to start investigating!

To turn off these messages

echo 0 > /proc/sys/vm/block_dump

I used a 64-bit machine; steps will be the same for 32-bit. If you have 64-bit and just want to download the kernel I used: http://bbis.us/~will/openvz-ubuntu810.tar.gz

Now let’s build the kernel.

cd /usr/src
wget http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.27.tar.bz2
tar xjf linux-2.6.27.tar.bz2
cd linux-2.6.27

wget http://download.openvz.org/kernel/branches/2.6.27/2.6.27-briullov.1/patches/patch-briullov.1-combined.gz
gunzip patch-briullov.1-combined.gz

wget http://download.openvz.org/kernel/branches/2.6.27/2.6.27-briullov.1/configs/kernel-2.6.27-x86_64.config.ovz
#OR
wget http://download.openvz.org/kernel/branches/2.6.27/2.6.27-briullov.1/configs/kernel-2.6.27-i686.config.ovz

cp kernel-2.6.27-*.config.ovz .config
patch -p1 < patch*

make oldconfig

make
make modules_install install

cd /boot
mkinitramfs -o /boot/initrd.img-2.6.27 2.6.27

vi /boot/grub/menu.lst

#Replace uuid entries with your disks uuid
title           Ubuntu 8.10 OpenVZ 2.6.27
uuid            2d5b2466-4bdf-44c7-b8e5-4d46a9f927c8
kernel          /boot/vmlinuz-2.6.27 root=UUID=2d5b2466-4bdf-44c7-b8e5-4d46a9f927c8 ro quiet splash
initrd          /boot/initrd.img-2.6.27
quiet

grub-install /dev/sda

apt-get install vzctl vzquota

reboot

If everything went according to plan, you’ll boot into your new kernel. If you get a kernel panic, or things are not working as expected, you may have to

make menuconfig

Once the kernel is working, let’s create a container.

cd /var/lib/vz/private

mkdir 1

debootstrap hardy 1

When you see:

#I: Base system installed successfully.

You can continue.

vi /etc/vz/dists/default
#Change redhat to debian OR copy ubuntu.conf to default

Create the container and set an IP

vzctl set 1 –applyconfig vps.basic –save
vzctl set 1 –ipadd 192.168.100.7 –save
vzctl set 1 –nameserver 192.168.100.1 –save

vzctl start 1

At this time you cannot enter the container. You will receive the error

Unable to open pty: No such file or directory

To fix this:

vzctl exec 1 update-rc.d -f udev remove

Restart and enter the container

vzctl restart 1

vzctl enter 1

If network doesn’t work add to /etc/sysctl.conf on server (not container):

net.ipv4.conf.default.forwarding=1
net.ipv4.conf.all.forwarding=1

apt-get install slapd ldap-utils libnss-ldap libpam-ldap migrationtools

Much like Debian, we must perform an extra step to make our changes permanent.

dpkg-reconfigure slapd

Omit OpenLDAP server configuration? No
DNS domain name: your-server
Organization name: whatever
Database backend to use: HDB
Do you want the database to be removed when slapd is purged? No
Move old database? Yes
Admin password: <password>
Confirm: <password>
Allow LDAPv2 protocol: No


Now we will populate LDAP. You should probably add a temporary LDAP user for testing. After we populate LDAP we’ll remove it.

adduser test
cd /usr/share/migrationtools


Edit migrate_common.ph and replace “padl.com” with your domain and dc=padl,dc=com with dc=YOUR,dc=DOMAIN

./migrate_base.pl > /tmp/base.ldif

./migrate_passwd.pl /etc/passwd /tmp/passwd.ldif

./migrate_group.pl /etc/group /tmp/group.ldif


Remove the top section of /tmp/base.ldif

dn: dc=dev
dc: dev
objectClass: top
objectClass: domain

Restart LDAP and add our information to LDAP


/etc/init.d/slapd restart

ldapadd -x -W -D 'cn=admin,dc=example,dc=net' < /tmp/base.ldif
ldapadd -x -W -D 'cn=admin,dc=example,dc=net' < /tmp/passwd.ldif
ldapadd -x -W -D 'cn=admin,dc=example,dc=net' < /tmp/group.ldif


To enable PAM I suggest


cd /tmp
wget http://st0rage.org/files/pam.d.tar
tar xf pam.d.tar -C /etc


Alternativly, you can try the following Ubuntu specific method:


auth-client-config -t nss -p lac_ldap
pam-auth-update ldap


Please note that I was unable to change user passwords with ‘passwd’ using this method.

Remove the test user

userdel test

Set up TLS Certificate

mkdir /etc/ldap/ssl
cd /etc/ldap/ssl

openssl req -new -nodes -out req.pem -keyout key.pem
#No challenge password, leave empty
openssl rsa -in key.pem -out new.key.pem
openssl x509 -in req.pem -out ca-cert -req -signkey new.key.pem -days 9999
mv new.key.pem server.pem
cat ca-cert >> server.pem


Enable TLS on server

ldapmodify -x -D cn=admin,cn=config -W

Paste in the following:

dn: cn=config
add: olcTLSCACertificateFile
olcTLSCACertificateFile: /etc/ldap/ssl/server.pem
-
add: olcTLSCertificateFile
olcTLSCertificateFile: /etc/ldap/ssl/server.pem
-
add: olcTLSCertificateKeyFile
olcTLSCertificateKeyFile: /etc/ldap/ssl/server.pem


Press ENTER a few times to finish modifying and then Control+C when you see:

modifying entry "cn=config"

Edit /etc/default/slapd and add

SLAPD_SERVICES="ldap:/// ldaps:/// ldapi:///"

Restart slapd

/etc/init.d/slapd restart

If it fails, try:


chown -R openldap /etc/ldap/ssl
/etc/init.d/slapd restart


Client configuration

vi /etc/ldap.conf

uri ldaps://server
port 636
ssl start_tls
ssl on
tls_checkpeer no
tls_cacertfile /etc/ldap/ssl/server.pem



vi /etc/nsswitch.conf

passwd: compat ldap
group: compat ldap
shadow: compat ldap
hosts: files dns
networks: files
protocols: db files
services: db files
ethers: db files
rpc: db files
netgroup: ldap

Now test! Make sure to stop nscd if you’re using it

/etc/init.d/nscd stop

Test LDAP

$ id test
uid=1001(test) gid=1001(test) groups=1001(test)


Remember to keep an eye on /var/log/auth.log if you run into any problems

If this is the case, you will notice that network speeds on the VM will not break 10/100 speeds.

To fix this, edit the xml file

vi /etc/libvirt/qemu/vm.xml

Make sure your network block looks like this (keep your MAC address the same)

<interface type='network'>
<mac address='00:16:36:0b:4c:9c'/>
<source network='default'/>
<model type='virtio'/>
</interface>


Shut down the VM and confirm it’s shut down

virsh shutdown vm

# virsh list
Connecting to uri: qemu:///system
Id Name                 State
----------------------------------


If you do not see your vm “running” you can proceed. If it’s still running you need to shut it down another way.

Update the xml definition

virsh define /etc/libvirt/qemu/vm.xml

Start the domain

virsh start vm

Log into the VM and test with a 1GB file

dd if=/dev/zero of=/tmp/test bs=1M count=1000
scp /tmp/test root@192.168.100.1:/tmp

You should see transfer speeds above 11-12 megabytes/second.

After enabling SSL and trying to add another SSL site, apache should refuse to restart and the following error would show up in /var/log/apache2.log

Digest: generating secret for digest authentication

After doing some research, it turns out that the VM did not have enough entropy to generate much of anything. Increasing this is easy, but may not be completely secure.

# cat /proc/sys/kernel/random/entropy_avail
139

# apt-get install rng-tools

# rngd -r /dev/urandom -o /dev/random

# cat /proc/sys/kernel/random/entropy_avail
2220

After running rngd, the entropy will increase at a gradual rate.

If you want this to survive a reboot, you’ll need to put it in a startup script.

As soon as I realized what had happened, I shut power off from the PC.

Booting to a live CD, I ran

mdadm –assemble /dev/md0 /dev/sda1 /dev/sdb1

fsck -y /dev/md0

I was able to then mount the drive

mkdir /media/md0

mount /dev/md0 /media/md0

ls /media/md0/lost+found

And the majority of my files were saved.

Check to see if your filesystem is ext2 or ext3

mount | grep md0

If it’s ext2, convert it to ext3

umount /media/md0

tune2fs -j /dev/md0

WARNING: If you choose to run fsck manually (without -y), choosing “n” to Clear? and “y” to Fix? will cause you to lose that file.

You first have to allow coredumps

vi /etc/security/limits.conf

*  -  core  100000

@users  -  core  0

core is measured in kbytes, and core files can be fairly large (the simple script below generates a 350kb file).  Do not set this to unlimited for regular users!

echo 1 > /proc/sys/kernel/core_uses_pid

mkdir /tmp/core

echo “/tmp/core/dump” > /proc/sys/kernel/core_pattern

ulimit -c 100000

To test it let’s create a script that will cause a coredump.

vi core_dump.sh

#!/bin/bash
#core_dump.sh
kill -s $$
#end

chmod +x core_dump.sh
./core_dump.sh

ls /tmp/cores

dump.14594 core_dump.sh

To view the corefile, you need gdb.

apt-get install gdb

gdb -c dump.13594