How to install Zabbix Server on Ubuntu

Zabbix is the enterprise-class open-source monitoring software for various IT components including server, network, virtual machine, cloud service, database, web monitoring, service, and storage device.

For installation of the Zabbix Server on Ubuntu, please watch the below video.

How to upgrade ubuntu server from Ubuntu 16.04 to Ubuntu 18.04

Ubuntu 16.04 LTS becomes EOL on Apr 2021. Ubuntu supports upgrade from one LTS to the next LTS in sequential order. To upgrade a server system follow the below steps. 

• Confirm OS version is Ubuntu 16.04 using command lsb_release –a 

• Update all the software packages repository list and upgrade packages on the existing system using the below command. It's recommended to reboot the system after all updates are applied. 

            sudo apt-get update

            sudo apt-get upgrade -y

            sudo apt-get dist-upgrade -y

• Install the Ubuntu Update Manager using the below command.

                    sudo apt-get install update-manager-core

• Make sure the Prompt line in /etc/update-manager/release-upgrades is set to 'lts' if you only want LTS upgrades.

• Upgrading to Ubuntu 18.04. To begin this process run the following command:

            sudo do-release-upgrade

• Before making any changes the above command will first verify whether the system is ready to update or not. The user will get prompted with information about the upgrade. Press Y to continue.
• After you enter the upgrade command, you will be asked to confirm that you want to update via SSH. Type Y to continue.

• Now Ubuntu will check for the packages that need the update and gives the information about the packages which will be added, removed, and the size of the update.

• The up-gradation process will take some time. During the up-gradation process, you may receive a prompt that will require your input. Kindly select a suitable option for you. You will have to select whether you want to install the new version of the file and overwrite the changes, keep the currently installed version, or merge the files.

• During the upgrade, it will ask to remove obsolete software Press Y to continue.

• After completion of the upgrade process, a system restart will be required.

• Post restart you may verify the Ubuntu version using lsb_release –a. 

KB: https://ubuntu.com/server/docs/upgrade-introduction

How to upgrade PostgreSQL9.5 to 12

PostgreSQL9.5 is the end of life now. You can use the steps mentioned in the below video to upgrade PostgreSQL9.5 to 12.

Before upgrade please make sure sufficient disk space is available. Some extensions like. PostGIS will not be upgraded during this process. You may drop the extension from 9.5, installed it on Postgres12, and create the extension. It's recommended to take a backup before doing the up-gradation process on the production environment.

Please find the below list of commands used in the up-gradation process. # Install the repository RPM:

sudo yum install -y https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm

# Install PostgreSQL9.5:

sudo yum install -y postgresql95-server

# Initialize the database and start service:

sudo /usr/pgsql-9.5/bin/postgresql95-setup initdb

# Install PostgreSQL12:

# Initialize the database and start service:

sudo yum install -y postgresql12-server

# PostgeSQL upgrade command syntax

sudo /usr/pgsql-12/bin/postgresql-12-setup initdb

# PostgeSQL Cluster compatibity check

pg_upgrade -b oldbindir -B newbindir -d oldconfigdir -D newconfigdir [option...]

/usr/pgsql-12/bin/pg_upgrade --old-bindir /usr/pgsql-9.5/bin/ --new-bindir /usr/pgsql-12/bin/ --old-datadir /var/lib/pgsql/9.5/data/ --new-datadir /var/lib/pgsql/12/data --link --check

# Upgrade Command /usr/pgsql-12/bin/pg_upgrade --old-bindir /usr/pgsql-9.5/bin/ --new-bindir /usr/pgsql-12/bin/ --old-datadir /var/lib/pgsql/9.5/data/ --new-datadir /var/lib/pgsql/12/data --link

Install PostgreSQL-12, pgAgent and PostGIS in CentOS 7

PostgreSQL is a free and open-source relational database management system and pgAgnet used for scheduling the job. PostgreSQL is also is known as Postgre. 

Please find the below steps to install PostgreSQL12, PostGIS, and pgAgnet in CentOS 7.

• Update Cent OS 7 and install EPEL repo

yum update

yum install epel-release

• Add the PostgreSQL12 Repository

You may find the repo of PostgreSQL 12 using link https://www.postgresql.org/download/linux/redhat/

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

• Install PostgresSQL12, pgAgnet and PostGIS

yum install postgresql12

yum install postgresql12-server

yum install pgagent_12

yum install postgis30_12

• Create a PostgreSQL data directory, set permission and set a password for postgres user

By default, Postgres data directory will be initializes at location /var/lib/pgsql/12/data. In this case, we use custom data directory.

mkdir /data/PG_DATA12
chown -R postgres:postgres /data/PG_DATA12
echo "postgres" | passwd --stdin postgres

• Initialize postgres database in a custom directory "/data/PG_DATA12"

su postgres -c "cd /usr/pgsql-12/bin/;./initdb -D /data/PG_DATA12" 

• Enable the service

systemctl enable postgresql-12 

• Change data directory path in postgresql-12.service

Open file postgresql-12.service which is located at /usr/lib/systemd/system/postgresql-12.service and replace "PGDATA=/var/lib/pgsql/12/data/" with "PGDATA=/data/PG_DATA12/". You may use below command also.

sed -i -e 's#Environment=PGDATA=/var/lib/pgsql/12/data/#Environment=PGDATA=/data/PG_DATA12/#g' /usr/lib/systemd/system/postgresql-12.service 

• Reload systemd 

systemctl daemon-reload

• Start and enable the service

systemctl start postgresql-12

systemctl enable pgagent_12

systemctl start pgagent_12 

• Change listen address in  postgresql.conf

 sed -i -e "s/^#listen_addresses = '127.0.0.1'/listen_addresses = '*' /g" /data/PG_DATA12/postgresql.conf

 sed -i -e "s/^#listen_addresses = 'localhost'/listen_addresses = '*' /g" /data/PG_DATA12/postgresql.conf

• Change authentication method from ident to trust in pg_hba.conf

sed -i -e "s#host    all all 127.0.0.1/32 ident#host    all all 127.0.0.1/32 trust#g" /data/PG_DATA12/pg_hba.conf

• Restart postgresql-12 and pgagent_12 service

    systemctl restart postgresql-12
    systemctl restart pgagent_12

• Create an extension for pgAgnet and PostGIS

psql -h localhost -p 5432 -U postgres -d template1 -c "CREATE EXTENSION postgis;"

psql -h localhost -p 5432 -U postgres -c "CREATE EXTENSION pgagent;"

• Start service

    systemctl start pgagent_12
    systemctl start postgresql-12