On Ubuntu, Google chrome had a disable native notification option. On Chrome 78, this option is removed. But you still can manually enable it.
To enbale chrome notification, edit file
gedit ~/.config/google-chrome/Local\ State
Find
"tab-hover-cards@4"
Replace with
"enable-native-notifications@2","tab-hover-cards@4"
Save and exit the file. Now restart google chrome.
Related Posts
virt-what is a shell script which can be used to detect if the program is running in a virtual machine.
It will identify what VM technology is used for current VM. For example KVM, Xen, HyperV etc.
On CentOS 7, install virt-what with
yum -y install virt-whatOn Debian/Ubuntu
apt install virt-whatExample
See VPS
apropos is a linux command that search manual pages and descriptions.
Example
root@mil-146068:~# apropos vagrant vagrant (1) - Tool for building and distributing virtualized development environments. dh_vagrant_plugin (1) - packaging helper for vagrant plugins root@mil-146068:~#
See Linux Commands
To see open files in linux use the command
lsof
There is a limit set in the kernel on how many open file descriptors are allowed on the system. This may be compiled in, or it may be tunable on the fly. In Linux, the value of this parameter can be read from and written to the proc filesystem.
[root@server50 home]# cat /proc/sys/fs/file-max 131072 [root@server50 home]#
On this system 1,31,072 open file descriptors are permitted. We are unlikely to run out. If we wanted to change it, we’d do something like this:
echo "132096" > /proc/sys/fs/file-max
But how do we know how many file descriptors are being used?
[root@server1 ~]# cat /proc/sys/fs/file-nr 1792 0 131072 | | | | | | | | maximum open file descriptors | total free allocated file descriptors total allocated file descriptors (the number of file descriptors allocated since boot)
On a server, df not showing all mounts
root@server20 [~]# df -h Filesystem Size Used Avail Use% Mounted on tmpfs 3.9G 0 3.9G 0% /dev/shm root@server20 [~]#
This is caused by corrupt /etc/mtab
To fix
mv /etc/mtab /etc/mtab.old cat /proc/mounts > /etc/mtab
See df
df command shows partitions and disks used by each partition.
root@server54 [~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 450G 380G 47G 90% / /dev/sda1 99M 11M 83M 12% /boot tmpfs 2.0G 0 2.0G 0% /dev/shm /dev/sdb1 458G 390G 46G 90% /backup /usr/tmpDSK 485M 63M 397M 14% /tmp root@server54 [~]#
To see partitions alone with Type, use
df -hT
WHen restoring a MySQL database, i get following error
root@ns3043014:~# mysql -u NEW_DB_USER -p'PASSOWRD_HERE' DB_NAME < BACKUP_FILE.sql ERROR 1227 (42000) at line 4382: Access denied; you need (at least one of) the SUPER privilege(s) for this operation root@ns3043014:~#
I opened the file in vim editor. On checking line 4382, i found following
/*!50013 DEFINER=`OLD_DB_USER`@`localhost` SQL SECURITY DEFINER */
This is because some stored procedures use old database user as definer. To fix you need to find and replace all entry for old username with new username.
In vim, i can run
:%s/OLD_DB_USER/NEW_DB_USER/g
Or delete the DEFINER line from SQL file.
sed 's/\sDEFINER=`[^`]*`@`[^`]*`//g' BACKUP_FILE.sql > BACKUP_FILE-modified.sql
Or
sed -i old 's/\DEFINER\=`[^`]*`@`[^`]*`//g' BACKUP_FILE.sql
Now restore BACKUP_FILE-modified.sql with
mysql -u NEW_DB_USER -p'PASSOWRD_HERE' DB_NAME < BACKUP_FILE-modified.sql
Unbound is an Open source DNS caching and recursive resolver. You can find more about unbound at
https://nlnetlabs.nl/projects/unbound/about/
To install unbound on Ubuntu/Debian, run
apt install unbound
To start unbound
systemctl start unbound
Set unbound to start on boot
systemctl enable unbound
To configure your server to use local name servers provided by unbound, edit file
vi /etc/resolv.conf
Add
nameserver 127.0.0.1
See dns
On CentovaCast server, icecast is run as user ccuser, to run icecast, you need to enable shell for this user. By defult, this user have shell access disabled.
ccuser:x:1001:1001::/usr/local/centovacast:/bin/false
running icecast manually maybe useful when you want to debug some issue with icecast.
To enable bash shell for user, run
chsh --shell /bin/bash ccuser
Login as user ccuser
su - ccuser
Now start icecast with
/usr/local/icecast/bin/icecast -c /usr/local/centovacast/var/vhosts/USER_HERE/etc/server.conf
Beofore you manually start icecast from terminal, make sure you stop icecast by logging into user in Centova Cast control panel.
See Centova Cast
Before you can get SSL work, you need to compile icecast with SSL. If icecast is not installed with SSL support, it will ignore
To install Icecast with SSL support, download Icecast from
cd /usr/local/src wget http://downloads.xiph.org/releases/icecast/icecast-2.4.4.tar.gz tar xvf icecast-2.4.4.tar.gz cd icecast-2.4.4 ./configure --prefix=/usr/serverok/icecast --with-curl --with-openssl
You need to verify SSL supported enabled. If you don’t have SSL support, you will see following error.
configure: SSL disabled!
If SSL enabled, you can verify it with
grep lssl config.status
You will see something like
[root@vmi173436 icecast-2.4.4]# grep lssl config.status S["XIPH_LIBS"]=" -lssl -lcrypto -lcurl -lspeex -ltheora -lvorbis -logg -L/usr/lib64 -lxslt -lxml2 -lz -ldl -lm " [root@vmi173436 icecast-2.4.4]#
If you get SSL disabled message, you need to install openssl-dev package
yum install -y openssl-devel
If SSL enabled, install icecast with
make make install
Replace icecast provided with CentovaCast with
mv /usr/local/icecast/bin/icecast /usr/local/icecast/bin/icecast-old ln -s /usr/serverok/icecast/bin/icecast /usr/local/icecast/bin/icecast
Enable SSL for stream
You need to edit icecast config for each user to do this. Config file stored at
vi /usr/local/centovacast/var/vhosts/USERNAME_HERE/etc/server.conf
Find
8005
Replace with
8005 9005 1
Here port 8005 is whatever port used by the stram. 9005 can be any unused port. It is better just use a port same format, so you know what port SSL will be running on.
Find
var/run/server.pid
Add Below
/usr/local/centovacast/etc/ssl/icecast.pem
ECDH+AESGCM:DH+AESGCM:ECDH+AES256:DH+AES256:ECDH+AES128:DH+AES:ECDH+3DES:DH+3DES:RSA+AESGCM:RSA+AES:RSA+3DES:!aNULL:!MD5:!DSS
Now create a file
vi /usr/local/centovacast/etc/ssl/icecast.pem
Paste your SSL in following order
1) Your private key 2) Your SSL cert 3) CA Bundle
Change owner of the SSL cert file
chown ccuser:ccuser /usr/local/centovacast/etc/ssl/icecast.pem
Stop and start icecast in CentovaCast.
Here is a server.conf file for a user with SSL enabled.
https://gist.github.com/serverok/57ae398bb94aa61d9945f2405c73e221
See Centova Cast
To install SSL on Centova Cast, edit file
vi /usr/local/centovacast/etc/ssl/certificate.pem
Add your SSL cert and ca-bundle file content to this file.
Edit
vi /usr/local/centovacast/etc/ssl/private.key
paste your private key.
Creae dhparam.
cd /usr/local/centovacast/etc/ssl/ openssl dhparam -out dhparam.pem 4096
Edi nginx config
vi /usr/local/centovacast/etc/cc-panel.conf
find
listen 2199 default ssl;
Add below
listen 443 ssl; listen 80;
Verify Nginx config is valid with
/usr/local/centovacast/sbin/cc-web -t
If all good, restart nginx with
/usr/local/centovacast/sbin/cc-web -s reload
Now Centova Cast can be accessed using HTTPS/SSL.
To set server time to PST/PDT, run
rm -f /etc/localtime ln -sf /usr/share/zoneinfo/America/Los_Angeles /etc/localtime
or
timedatectl set-timezone America/Los_Angeles