Deploy TiDB Offline Using TiDB Ansible

This guide describes how to deploy a TiDB cluster offline using TiDB Ansible.

Prepare

Before you start, make sure that you have:

A download machine
- The machine must have access to the Internet in order to download TiDB Ansible, TiDB and related packages.
- For Linux operating system, it is recommended to install CentOS 7.3 or later.
Several target machines and one Control Machine
- For system requirements and configuration, see Prepare the environment.
- It is acceptable without access to the Internet.

Step 1: Install system dependencies on the Control Machine

Take the following steps to install system dependencies on the Control Machine installed with the CentOS 7 system.

Download the pip offline installation package on the download machine and then upload it to the Control Machine.
Note:
This offline installation package includes pip and sshpass, and only supports the CentOS 7 system.

Install system dependencies on the Control Machine.

tar -xzvf ansible-system-rpms.el7.tar.gz &&
cd ansible-system-rpms.el7 &&
chmod u+x install_ansible_system_rpms.sh &&
./install_ansible_system_rpms.sh

After the installation is finished, you can use pip -V to check whether it is successfully installed.
```
pip -V
```
```
pip 8.1.2 from /usr/lib/python2.7/site-packages (python 2.7)
```

Note:
If pip is already installed to your system, make sure that the version is 8.1.2 or later. Otherwise, compatibility error occurs when you install TiDB Ansible and its dependencies offline.

Step 2: Create the `tidb` user on the Control Machine and generate the SSH key

See Create the tidb user on the Control Machine and generate the SSH key.

Step 3: Install TiDB Ansible and its dependencies offline on the Control Machine

Currently, all the versions of TiDB Ansible from 2.4 to 2.7.11 are supported. The versions of TiDB Ansible and the related dependencies are listed in the tidb-ansible/requirements.txt file. The following installation steps take Ansible 2.5 as an example.

Download Ansible 2.5 offline installation package on the download machine and then upload it to the Control Machine.

Install TiDB Ansible and its dependencies offline.

tar -xzvf ansible-2.5.0-pip.tar.gz &&
cd ansible-2.5.0-pip/ &&
chmod u+x install_ansible.sh &&
./install_ansible.sh

View the version of TiDB Ansible.
After TiDB Ansible is installed, you can view the version using ansible --version.
```
ansible --version
```
```
ansible 2.5.0
```

Step 4: Download TiDB Ansible and TiDB packages on the download machine

Install TiDB Ansible on the download machine.
Use the following method to install Ansible online on the download machine installed with the CentOS 7 system. After TiDB Ansible is installed, you can view the version using ansible --version.
```
yum install epel-release &&
yum install ansible curl &&
ansible --version
```
```
ansible 2.5.0
```
Note:
Make sure that the version of Ansible is 2.5, otherwise a compatibility issue occurs.
Download TiDB Ansible.
Use the following command to download TiDB 3.0 version with the corresponding tag from the TiDB Ansible project GitHub repo. The default folder name is tidb-ansible.
```
git clone -b $tag https://github.com/pingcap/tidb-ansible.git
```
Note:
- Replace $tag with the value of the selected tag version, such as v3.0.2.
- It is required to use the corresponding tidb-ansible version when you deploy and upgrade the TiDB cluster. If you deploy TiDB using a mismatched version of tidb-ansible (such as using tidb-ansible v2.1.4 to deploy TiDB v2.1.6), an error might occur.
Run the local_prepare.yml playbook, and download TiDB binary online to the download machine.
```
cd tidb-ansible &&
ansible-playbook local_prepare.yml
```
After running the above command, copy the tidb-ansible folder to the /home/tidb directory of the Control Machine. The ownership authority of the file must be the tidb user.

Step 5: Configure the SSH mutual trust and sudo rules on the Control Machine

See Configure the SSH mutual trust and sudo rules on the Control Machine.

Step 6: Install the NTP service on the target machines

See Install the NTP service on the target machines.

Note:
If the time and time zone of all your target machines are same, the NTP service is on and is normally synchronizing time, you can skip this step. See How to check whether the NTP service is normal.