How to Setup Odoo 14 in CentOS 7

Odoo is currently one of the most popular tool for business purposes. It has a community edition, that allows managing ERP at very low cost. Odoo was previously known as OpenERP. Odoo requires to be installed on a dedicated server or VPS. Odoo 14 had come out already. I will have a straight forward how to on installing the latest Odoo 14 in CentOS 7.

Log in to your system and update

First step would be to login to your system and then update the system using yum.

ssh [email protected]_ip

You may check the CentOS version from the redhat release file using the following:

cat /etc/redhat-release

It should show you something like the following if you

CentOS Linux release 7.8.2003 (Core)

Now, you may try updating the system with yum

yum update -y

Once done, now install the EPEL repository as we need it to satisfy a couple of dependecies:

yum install epel-release

Install Python 3.6 packages and Odoo dependencies

We need Python 3.6 at least to run Odoo 14. Odoo 13 also ran on Python 3.6. We will use ‘Software Collection (scl)’ repository to install and use Python 3.6. To find the available Python versions in SCL, you may check the following:

SCL Repository for Python

Now, to install Python 3.6 using SCL, we first need to install the SCL repository for Centos:

yum install centos-release-scl

Once the SCL is loaded, now, you may install the python 3.6 using the following command:

yum install rh-python36

Once the Python is installed, now we will install several tools and packages for Odoo dependencies with the following command:

yum install git gcc nano wget nodejs-less libxslt-devel bzip2-devel openldap-devel libjpeg-devel freetype-devel

Create Odoo User

We now need to create a system user and group for Odoo and define a home directory to /opt/odoo

useradd -m -U -r -d  /opt/odoo -s /bin/bash odoo

You may use any username here, but remember to create the same username for the PostgreSQL as well.

Install PostgreSQL

CentOS base repository unfortunately, comes with Postgresql 9.2. But we want to use PostgreSQL 10 for our Odoo installation. You may check the available PostgreSQL for CentOS 7 using the following command:

yum list postgresql*

As by default CentOS 7 does not provide the PostgreSQL 10, we would use PostgreSQL official repository to download and install the 10 version.

First, we install the Postgres Yum Repository using the following command:

yum install https://download.postgresql.org/pub/repos/yum/10/redhat/rhel-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm

Now, you may install PostgreSQL 10 and related required packages using the following command:

yum install postgresql10 postgresql10-server postgresql10-contrib postgresql10-libs -y

Now, we need to initialize the postgres database and start it. You may do that using the following:

# Initialize the DB
/usr/pgsql-10/bin/postgresql-10-setup initdb

# Start the database
systemctl start postgresql-10.service

If everything goes alright, now you may check the postgresql 10 status:

[[email protected] bin]# systemctl status postgresql-10.service
● postgresql-10.service - PostgreSQL 10 database server
   Loaded: loaded (/usr/lib/systemd/system/postgresql-10.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2021-04-05 16:42:15 EDT; 5s ago
     Docs: https://www.postgresql.org/docs/10/static/
  Process: 6380 ExecStartPre=/usr/pgsql-10/bin/postgresql-10-check-db-dir ${PGDATA} (code=exited, status=0/SUCCESS)
 Main PID: 6386 (postmaster)
    Tasks: 8
   Memory: 13.5M
   CGroup: /system.slice/postgresql-10.service
           ├─6386 /usr/pgsql-10/bin/postmaster -D /var/lib/pgsql/10/data/
           ├─6388 postgres: logger process
           ├─6390 postgres: checkpointer process
           ├─6391 postgres: writer process
           ├─6392 postgres: wal writer process
           ├─6393 postgres: autovacuum launcher process
           ├─6394 postgres: stats collector process
           └─6395 postgres: bgworker: logical replication launcher

Now you may enable Postgres to start when booting up using the systemctl enable command:

systemctl enable postgresql-10.service

Now, we need to create a database user for our Odoo installation. You may do that using the following:

su - postgres -c "createuser -s odoo"

Note: If you have created a different user for Odoo installation other than ‘odoo’ than you should change the username here as well.

Install Wkhtmltopdf

Wkhtmltopdf is a open source tool to make html in pdf format so that you may print pdf reports. This tool is used by Odoo and requires to be installed as dependency. CentOS 7 repository does not provide the latest version of this tool, and Odoo requires you to use the latest version. Hence, we require to download the latest version from the Wkhtmltopdf website and install it. To do that, you may first visit the page:

https://wkhtmltopdf.org/downloads.html

The page gives you the direct rpm download link for each version of CentOS/Ubuntu/Mac etc. Download the stable version for CentOS 7. At the time of writing, the URL for CentOS 7 x86_64 bit is the following:

https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox-0.12.6-1.centos7.x86_64.rpm

You may install this using the following:

cd /opt/
wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox-0.12.6-1.centos7.x86_64.rpm
yum localinstall wkhtmltox-0.12.6-1.centos7.x86_64.rpm

Install and Configure Odoo 14

If you have come all through here, that means you are done with the all dependency installations before starting to download Odoo 14 source code. We will download Odoo 14 from it’s Github repo and use virtualenv to create an isolated python environment to install this python software.

First, login as odoo from root:

su - odoo

Clone the Odoo source code from Github repository:

git clone https://www.github.com/odoo/odoo --depth 1 --branch 14.0 /opt/odoo/odoo14

This will bring the Odoo 14 branch from the Odoo repository and put it inside the folder /opt/odoo/odoo14

Now, we need to enable software collections in order to access python binaries:

scl enable rh-python36 bash

Then we need to create a virtual environment to complete the installation:

cd /opt/odoo
python3 -m venv odoo14-venv

Now, you may activate the virtual environment you have just created:

source odoo14-venv/bin/activate

Now, we upgrade the pip and install the wheel library:

pip install --upgrade pip
pip3 install wheel

Once done, now we can using pip3 to install all the required Python modules from the requirements.txt file:

pip3 install -r odoo14/requirements.txt

Once the installation is complete, now we can deactivate the virtual environment and get back to the root user

deactivate && exit ; exit

If you think, you will create custom modules, you may now create it and give odoo the permission accordingly:

mkdir /opt/odoo/odoo14-custom-addons
chown odoo: /opt/odoo/odoo14-custom-addons

Now, we can fill up the odoo configuration file. First open the odoo.conf file:

nano /etc/odoo.conf

You may paste the following inside:

[options]
; This is the password that allows database operations:
admin_passwd = set_the_password_to_create_odoo_database
db_host = False
db_port = False
db_user = odoo
db_password = False
addons_path = /opt/odoo/odoo14/addons,/opt/odoo/odoo14-custom-addons
; You can enable log file with uncommenting the next line
; logfile = /var/log/odoo14/odoo.log

Please do not forget to change the password ‘set_the_password_to_create_odoo_database’ with a new strong password. This would be used to create Odoo databases from the login screen.

Create the systemd service file and start Odoo 14

Now, we will create a service file, to be able to start, stop and restart Odoo daemon. To do that, first create a service file using the following:

nano /etc/systemd/system/odoo14.service
[Unit]
Description=Odoo14
Requires=postgresql-10.service
After=network.target postgresql-10.service
[Service]
Type=simple
SyslogIdentifier=odoo14
PermissionsStartOnly=true
User=odoo
Group=odoo
ExecStart=/usr/bin/scl enable rh-python36 -- /opt/odoo/odoo14-venv/bin/python3 /opt/odoo/odoo14/odoo-bin -c /etc/odoo.conf
StandardOutput=journal+console
[Install]
WantedBy=multi-user.target

Now, save the file and exit.

Now, you need to reload the systemd daemon to be able to read the latest changes you have made to services. To do that, run:

systemctl daemon-reload

Finally, now we can start Odoo 14 instance using the following command:

systemctl start odoo14

If you are interested to check the status of the instance, you may do this:

systemctl status odoo14

It show green active running, if everything worked out. If you see no error, you may now enable Odoo to start during the boot:

systemctl enable odoo14

If you would like to see the logs, you may either use the journal tools like the following:

journalctl -u odoo14

or uncomment the following line to log the debugs in /etc/odoo.conf

logfile = /var/log/odoo14/odoo.log

After making any change to /etc/odoo.conf, do not forget the restart the Odoo14 instance using systemctl.

Test the Installation


Odoo is currently one of the most popular tool for business purposes. It has a community edition, that allows managing ERP at very low cost. Odoo was previously known as OpenERP. Odoo requires to be installed on a dedicated server or VPS. Odoo 13 had come out on October, 2019. Odoo 14 hasn’t been released yet for production. I will have a straight forward how to on installing the latest Odoo 13 in CentOS 7.

Log in to your system and update

First step would be to login to your system and then update the system using yum.ssh [email protected]_ip

You may check the CentOS version from the redhat release file using the following:cat /etc/redhat-release

It should show you something like the following if youCentOS Linux release 7.8.2003 (Core)

Now, you may try updating the system with yumyum update -y

Once done, now install the EPEL repository as we need it to satisfy a couple of dependecies:yum install epel-release

Install Python 3.6 packages and Odoo dependencies

We need Python 3.6 at least to run Odoo 13. Odoo 12 had support for Python 3.5, unfortunately, Odoo 13 doesn’t. We will use ‘Software Collection (scl)’ repository to install and use Python 3.6. To find the available Python versions in SCL, you may check the following:

SCL Repository for Python

Now, to install Python 3.6 using SCL, we first need to install the SCL repository for Centos:yum install centos-release-scl

Once the SCL is loaded, now, you may install the python 3.6 using the following command:yum install rh-python36

Once the Python is installed, now we will install several tools and packages for Odoo dependencies with the following command:yum install git gcc nano wget nodejs-less libxslt-devel bzip2-devel openldap-devel libjpeg-devel freetype-devel

Create Odoo User

We now need to create a system user and group for Odoo and define a home directory to /opt/odoouseradd -m -U -r -d /opt/odoo -s /bin/bash odoo

You may use any username here, but remember to create the same username for the PostgreSQL as well.

Install PostgreSQL

CentOS base repository unfortunately, comes with Postgresql 9.2. But we want to use PostgreSQL 9.6 for our Odoo installation. You may check the available PostgreSQL for CentOS 7 using the following command:yum list postgresql*

As by default CentOS 7 does not provide the PostgreSQL 9.6, we would use PostgreSQL official repository to download and install the 9.6 version.

First, we install the Postgres Yum Repository using the following command:yum install https://download.postgresql.org/pub/repos/yum/9.6/redhat/rhel-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm

Now, you may install PostgreSQL 9.6 and related required packages using the following command:yum install postgresql96 postgresql96-server postgresql96-contrib postgresql96-libs

Now, we need to initialize the postgres database and start it. You may do that using the following:# Initialize the DB/usr/pgsql-9.6/bin/postgresql96-setup initdb# Start the databasesystemctl start postgresql-9.6.service

Now you may enable Postgres to start when booting up using the systemctl enable command:systemctl enable postgresql-9.6.service

Now, we need to create a database user for our Odoo installation. You may do that using the following:su – postgres -c “createuser -s odoo”

Note: If you have created a different user for Odoo installation other than ‘odoo’ than you should change the username here as well.

Install Wkhtmltopdf

Wkhtmltopdf is a open source tool to make html in pdf format so that you may print pdf reports. This tool is used by Odoo and requires to be installed as dependency. CentOS 7 repository does not provide the latest version of this tool, and Odoo requires you to use the latest version. Hence, we require to download the latest version from the Wkhtmltopdf website and install it. To do that, you may first visit the page:https://wkhtmltopdf.org/downloads.html

The page gives you the direct rpm download link for each version of CentOS/Ubuntu/Mac etc. Download the stable version for CentOS 7. At the time of writing, the URL for CentOS 7 x86_64 bit is the following:https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox-0.12.6-1.centos7.x86_64.rpm

You may install this using the following:cd /opt/wget https://github.com/wkhtmltopdf/packaging/releases/download/0.12.6-1/wkhtmltox-0.12.6-1.centos7.x86_64.rpmyum localinstall wkhtmltox-0.12.6-1.centos7.x86_64.rpm

Install and Configure Odoo 13

If you have come all through here, that means you are done with the all dependency installations before starting to download Odoo 13 source code. We will download Odoo 13 from it’s Github repo and use virtualenv to create an isolated python environment to install this python software.

First, login as odoo from root:su – odoo

Clone the Odoo source code from Github repository:git clone https://www.github.com/odoo/odoo –depth 1 –branch 13.0 /opt/odoo/odoo13

This will bring the Odoo 13 branch from the Odoo repository and put it inside the folder /opt/odoo/odoo13

Now, we need to enable software collections in order to access python binaries:scl enable rh-python36 bash

Then we need to create a virtual environment to complete the installation:cd /opt/odoopython3 -m venv odoo13-venv

Now, you may activate the virtual environment you have just created:source odoo13-venv/bin/activate

Now, we upgrade the pip and install the wheel library:pip install –upgrade pippip3 install wheel

Once done, now we can using pip3 to install all the required Python modules from the requirements.txt file:pip3 install -r odoo13/requirements.txt

Once the installation is complete, now we can deactivate the virtual environment and get back to the root userdeactivate && exit ; exit

If you think, you will create custom modules, you may now create it and give odoo the permission accordingly:mkdir /opt/odoo/odoo13-custom-addonschown odoo: /opt/odoo/odoo13-custom-addons

Now, we can fill up the odoo configuration file. First open the odoo.conf file:nano /etc/odoo.conf

You may paste the following inside:[options]; This is the password that allows database operations:admin_passwd = set_the_password_to_create_odoo_databasedb_host = Falsedb_port = Falsedb_user = odoodb_password = Falseaddons_path = /opt/odoo/odoo13/addons,/opt/odoo/odoo13-custom-addons; You can enable log file with uncommenting the next line; logfile = /var/log/odoo13/odoo.log

Please do not forget to change the password ‘set_the_password_to_create_odoo_database’ with a new strong password. This would be used to create Odoo databases from the login screen.

Create the systemd service file and start Odoo 13

Now, we will create a service file, to be able to start, stop and restart Odoo daemon. To do that, first create a service file using the following:nano /etc/systemd/system/odoo13.service

and paste the following:[Unit]Description=Odoo13Requires=postgresql-9.6.serviceAfter=network.target postgresql-9.6.service[Service]Type=simpleSyslogIdentifier=odoo13PermissionsStartOnly=trueUser=odooGroup=odooExecStart=/usr/bin/scl enable rh-python35 — /opt/odoo/odoo13-venv/bin/python3 /opt/odoo/odoo13/odoo-bin -c /etc/odoo.confStandardOutput=journal+console[Install]WantedBy=multi-user.target

Now, save the file and exit.

Now, you need to reload the systemd daemon to be able to read the latest changes you have made to services. To do that, run:systemctl daemon-reload

Finally, now we can start Odoo 13 instance using the following command:systemctl start odoo13

If you are interested to check the status of the instance, you may do this:systemctl status odoo13[[email protected] ~]# systemctl status odoo13● odoo13.service – Odoo13 Loaded: loaded (/etc/systemd/system/odoo13.service; enabled; vendor preset: disabled) Active: active (running) since Sun 2020-09-13 08:26:46 EDT; 23h ago Main PID: 24502 (scl) CGroup: /system.slice/odoo13.service ├─24502 /usr/bin/scl enable rh-python36 — /opt/odoo/odoo13-venv/bin/python3 /opt/odoo/odoo13/odoo-bin -c /etc/odoo.conf ├─24503 /bin/bash /var/tmp/sclSWH04z └─24507 /opt/odoo/odoo13-venv/bin/python3 /opt/odoo/odoo13/odoo-bin -c /etc/odoo.conf

It show green active running, if everything worked out. If you see no error, you may now enable Odoo to start during the boot:systemctl enable odoo13

If you would like to see the logs, you may either use the journal tools like the following:journalctl -u odoo13

or uncomment the following line to log the debugs in /etc/odoo.conflogfile = /var/log/odoo13/odoo.log

After making any change to /etc/odoo.conf, do not forget the restart the Odoo13 instance using systemctl.

Test the Installation

You may now test the installation using http://your_server_ip:8069. If everything worked, it should come up. If it doesn’t, you may try stopping your ‘firewalld’ to see if firewall is blocking the port or not:

systemctl stop firewalld

At Mellowhost, we provide Odoo installation and configuration assistance for absolute free of charge. If you are willing to try out any of our VPS for Odoo, you may do so and talk with us through the Live chat or the ticket for Odoo assistance.

Furthermore, Good luck.

How to Speed Up Software RAID (mdadm) Resync Speed

mdadm is the software raid tools used in Linux system. One key problem with the software raid, is that it resync is utterly slow comparing with the existing drive speed (SSD or NVMe). The resync speed set by mdadm is default for regardless of whatever the drive type you have. To view the default values, you may run the following:

[[email protected] ~]# sysctl dev.raid.speed_limit_min
dev.raid.speed_limit_min = 1000
[[email protected] ~]# sysctl dev.raid.speed_limit_max
dev.raid.speed_limit_max = 200000

As you see, the minimum value starts from 1000 and can max upto 200K. Although, it can max upto 200K, but as min value is too low, mdadm always tries to keep the value below average to your speed available. To speed up, we would like to maximize these numbers. To change the numbers, you may run something like the following:

sysctl -w dev.raid.speed_limit_min=500000
sysctl -w dev.raid.speed_limit_max=5000000

Once done, you may now check the speed is going up immediately:

[[email protected] ~]# cat /proc/mdstat
Personalities : [raid1]
md3 : active raid1 sdb5[1] sda5[0]
      1916378112 blocks super 1.2 [2/2] [UU]
      [===============>.....]  resync = 76.2% (1461787904/1916378112) finish=27.4min speed=276182K/sec
      bitmap: 5/15 pages [20KB], 65536KB chunk

md0 : active raid1 sdb1[1] sda1[0]
      1046528 blocks super 1.2 [2/2] [UU]
      bitmap: 0/1 pages [0KB], 65536KB chunk

md2 : active raid1 sda2[0] sdb2[1]
      78576640 blocks super 1.2 [2/2] [UU]
      bitmap: 1/1 pages [4KB], 65536KB chunk

md1 : active raid1 sdb3[1] sda3[0]
      4189184 blocks super 1.2 [2/2] [UU]

unused devices: <none>

One thing to keep in mind is that, if you try to set the value too high, like we did, this might cause some handsome load on your system. If you see the load is unmanageable, you should focus on decreasing the number to something like 50k-100k for the min value.

Making The Sysctl Value Permanent

As we have established the kernel variable values on runtime, this would go back to default once we restart/reboot the server. If you want to persist the values, you need to put these values to /etc/sysctl.conf file. To make them persist, open the sysctl.conf file:

nano /etc/sysctl.conf

Add the following lines at the end of the file:

dev.raid.speed_limit_min = 500000
dev.raid.speed_limit_max = 5000000

Save the file, and run the following command:

sysctl -p

This should persist your values for those variables after the reboot as well as runtime.

-bash: smartctl: command not found

Error Details

When I try to check the S.M.A.R.T details of my drive, using the following command:

smartctl -a /dev/sda

I get an error:

-bash: smartctl: command not found

What can I do?

Solution

This error is appearing because you do not have the S.M.A.R.T tools installed on your system.

How to Install Smart tools on CentOS 7?

To install smart tools, you can run the following:

yum install smartmontools -y

Once done, you may run the smartctl command again, and it shall work:

[[email protected] ~]# smartctl -a /dev/sda
smartctl 7.0 2018-12-30 r4883 [x86_64-linux-3.10.0-1127.el7.x86_64] (local build)
Copyright (C) 2002-18, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Crucial/Micron BX/MX1/2/3/500, M5/600, 1100 SSDs
Device Model:     Micron_1100_MTFDDAK2T0TBN

How to Disable Clamd & Spamassasign in Virtualmin

Question

My clamscan is taking a lot of CPU & memory of my vps. I use Virtualmin as the control panel. How can I disable Clamscan and Spamassign from taking excessive cpu and memory?

Solution

If you are receiving an inbound spam attack or an email bounce attack on your VPS, and you use Clamscan and Spamassasign for your incoming mail filtering, it is highly possible that, you will run out of RAM and CPU. To solve the problem, you need to disable Clamscan and Spamassign for at least the time you are dealing with the attack or have developed a way to deal the attack. To disable Clamd and Spamassasign, you may follow the following steps

How to Disable Clamd and Spamassasign

First login to your virtualmin 10000 port, and go to System Settings >> Features and Plugins

Now uncheck the options ‘Spam filtering’ and ‘Virus filtering’ option and save it

Now go to your Webmin tab >> Under the System >> Bootup and Shutdown

Now select the services with the name ‘clam’ and ‘spamassassin.service’, then click on ‘Disable now and on boot’ option. Once saved, also make sure they are saying ‘No’ in running. If not, select them again and go to the bottom of the page, and press ‘Stop’ to shut them down immediately.

How to Restart Virtualmin / Webmin

Question

How to restart Virtualmin control panel?

Solution

If you are using virtualmin as a control panel, you use 10000 port to login to your control panel. It shall look like the following:

https://your.hostname.com:10000

Now, if your browser says something like the following:

It means your webmin is either down or crashed.

Restart Virtualmin or Restart Webmin

To solve this, you may start the webmin by logging to your SSH and running the following command:

service webmin start
or
/etc/init.d/webmin start

In case, you need to double sure to stop the service, you may do the following:

service webmin stop
or
/etc/init.d/webmin stop

Once you done, stopping, make sure to start it with the following:

service webmin start
or
/etc/init.d/webmin start

Once the webmin starts successfully, you may access your virtulmin control panel on port 10000, either with your hostname or the IP, like the following:

https://your.hostname.com:10000
or
https://11.11.11.11:10000
(replace 11.11.11.11 with your server IP)

How to Change memory_limit in Virtualmin

Question

I want to change the memory_limit of a virtual host in virtualmin. How can I do that?

Solution

First, login to Virtualmin on port 10000, now, select the virtual host from the dropdown under Virtualmin tab. Now under the services, there are PHP 5 Configuration and PHP 7 Configuration

Click on the version you want to change configuration for. It will show you a list of options to change php variables.

Now there is ‘Resource Limit’, that contains the options like maximum execution time, or memory limit for PHP.

Now, change the ‘Maximum Memory Allocation’ option to something that you want to change memory_limit of php in virtualmin

Server Boots to Grub – OVH Servers – How to Fix

Error Details

After you have completed updating your yum, you saw the kernel got updated, and hence restarted the server to take the new kernel. But you find out that the server has never come online. Once you visit the KVM or Serial Console (SOL) of the system, you could see, your system is booted to ‘grub>’ console instead of booting from disk. How can you fix the system now?

Solution Intro

This specific issue can appear for any linux server, along with many reasons. Although, if you are running an server from OVH and had faced a similar issue, the boat I am going to show you can navigate to destination. Please note, in many other case of similar situation, you might end up fixing the grub with the same solution.

What and How the Problem Happened

OVH has an interesting strategy of booting. They follow everything through network PXE, even if it is not ‘netboot’, but just the local drives. For this to work out, you need PXE to take the latest grub details pushed once a kernel is updated. This is one reason why, OVH also supplies a custom kernel from a cusstom repo. Although, if you are using the stock kernel, you might come up with a situation, where the latest grub hasn’t been pushed to PXE and your system fails to boot from drives. It then puts you in the ‘grub’ of network.

How to Fix the Problem

Now, one thing is clear, after you completed a kernel update, your grub is broken due to the latest machine code is not available to the booting system. You can go and follow a regular grub repair method for Grub 2, to fix the situation. A couple of things to remember, as your system’s grub is failing to load, you have to use an independent rescue kernel to fix this, this could either be from a personal network repository or a rescue disk available from your datacenter’s location, like ovh has one. Another thing to remember, is that, if you are using CentOS 7 or Ubuntu with UEFI system, using mdadm or linux software raid, it is highly likely, your boot efi is placed in a non raid partition. Preferably in the first drive’s first partition. You can always verify this from your fstab file.

So the first job, is to boot your system into the rescue disk/cd/kernel. I assume you have done that with no difficulty. Once done, first mount your partitions. In OVH cases, it loads the mdadm automatically. In my case, it was /dev/md2.

mount /dev/md2 /mnt
# check what partition is used for /boot/efi
nano /mnt/etc/fstab
# in my case, it is /dev/nvme0n1p1 (It is a NVMe SSD, and the first partion is used for efi storage
mount /dev/nvme0n1p1 /mnt/boot/efi

Once we have mounted the partitions successfully, you may now chroot the system. Before chrooting, you want the dev, proc and sys to use the /mnt partitions respectively:

mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys

If these all goes well, now we can chroot the system:

chroot /mnt

Now you have successfully changed the root directory of the rescue kernel to the original drive’s root. All you need to do, is to remake the grub config, that will immediately generate the grub.cfg file and sync the machine code:

# we know grub.cfg is available in /boot/grub2/grub.cfg
grub2-mkconfig -o  /boot/grub2/grub.cfg
# once this is finished, we have to make sure, grub is also installed for both disks, for my case, these are /dev/nvme0n1 and /dev/nvme1n1
grub2-install /dev/nvme0n1
grub2-install /dev/nvme1n1

If you see the response is ‘No Error Reported’, then you are good go. You may now reboot your system back to hard disk, and can see your grub is able to load the latest kernel you installed from the original hard disk. Remember, for safety, you should umount all the partition, to avoid any data loss due to OS page cache:

# exit from chroot
exit
# unmount dev, proc, sys, /mnt/boot/efi, /mnt
umount /dev
umount /proc
umount /sys
umount /mnt/boot/efi
umount /mnt

Happy troubleshooting!

How to run composer with different PHP versions in Cpanel?

Question:

When we try to run a composer command, like update, we usually do the following:

composer update

Cpanel has multiple PHP binaries, but in this case, we are unable to select a specific PHP binary to use, instead we have to run it with the default one, how to run composer update with a different php binary in cpanel?

Solution

composer binary file, is a phar file. PHAR is necessarily a PHP Archive and usually automatically detect the running php. But as it is essentially written in php, you may explicitly run it with a different php binary, if you want. To run composer with different php binary, first, you need to find the location of composer. You may do so, using the following:

[email protected] [~]# which composer
/opt/cpanel/composer/bin/composer

Cpanel different php binaries are available under the following kind of directory:

/opt/cpanel/ea-phpXX/usr/bin/php

XX is the version number of PHP. So for example if you need to use PHP 7.4, you would need to run using the following:

/opt/cpanel/ea-php74/usr/bin/php

Now, to run composer update along with PHP 7.4 binary, you may do something like the following:

/opt/cpanel/ea-php74/usr/bin/php /opt/cpanel/composer/bin/composer update

First, make sure you are in the directory where you want to install laravel, for example, something like the following:

cd /home/username/public_html

Then, you may run the above command:

/opt/cpanel/ea-php74/usr/bin/php /opt/cpanel/composer/bin/composer update
or in case, you want to to install
/opt/cpanel/ea-php74/usr/bin/php /opt/cpanel/composer/bin/composer install
or may be, you wan to run update with no-scripts
/opt/cpanel/ea-php74/usr/bin/php /opt/cpanel/composer/bin/composer update --no-scripts

Uncaught ErrorException: require(/home/username/public_html/vendor/composer/../../app/Helpers/helper.php): failed to open stream: No such file or directory in /home/username/public_html/vendor/composer/autoload_real.php:71

Error Details

While trying to run any of the following with Laravel composer installer, you see an error similar to the following:

Uncaught ErrorException: require(/home/username/public_html/vendor/composer/../../app/Helpers/helper.php): failed to open stream: No such file or directory in /home/username/public_html/vendor/composer/autoload_real.php:71

How to fix this?

Solution

The error is appearing, most likely you forgot to add the ‘app’ directory of laravel in your root directory. Make sure, you have the ‘app’ directory in your root directory, then run any of the following:

If this is the first time, you need all laravel packages, run:

composer install

If this is not the first time, you may run the following:

composer update

Good luck.

How to Backup PostgreSQL Database from Command Line

Question

How to Backup PostgreSQL Database from Command Line

Solution

Postgresql comes with two utilities called ‘pg_dump and ‘pgsql’. These can be used to backup and restore database.

To backup postgresql database using command line, you can use this:

pg_dump database_name > database_name.sql

This would take the backup and store it in .sql file.

To restore postgresql (.sql) file to a database using command line, you can use this:

pgsql database_name &lt; database_name.sql