Practical Tips for linux: practical tips for using snapshots to create virtual machines and linux

Practical Tips for linux: practical tips for using snapshots to create virtual machines and linux
In daily learning, if you encounter cluster and load balancing experiments, you need to use a large number of virtual machines. If you create one by one, it is obviously very cost-effective and inefficient. So how can we use snapshots to create virtual machines today. The number of bytes _ ^ you want. As long as the memory is enough!

To create a snapshot of a VM, perform the following steps:

1. First, we need to create a stored logical volume to generate the template and snapshot file;
2. Create a snapshot template;
3. Create a snapshot.

1. Create a logical volume:

(1) fdisk/dev/sda (create an LVM logical volume and then re-scan the disk ;)


(2) partx-d/dev/sda
Partx-a/dev/sda

(3) create an lv file:

Pvcreate/dev/sda
Vgcreate-s 4 M vg1/dev/sda5
Lvcreate-L 10G-n base vg1

(4) Then you can create a virtual machine template:





In this case, you can install an ordinary virtual machine. After the restart, perform the following operations (because you have created a template, the template must be universal)

2. Create a template:

In the template virtual machine, perform the following operations:

1. Disable firewall and selinux (File Modification ):



Vim/etc/sysconfig/selinux


2. Modify the network configuration file and delete the NIC information:

Vim/etc/sysconfig/network-script/ifcfg-eth0




3. Modify the yum source to a stable address:

Vim/etc/yum. repos. d/yum. repo





3. Create a snapshot:

After the template is completed, you can use a snapshot to take a photo of it on the real machine. However, you must disable the template before taking the photo, usually, when we take a photo of a person, we also need his static ^_^.





Select the snapshot file:



Directly start vm2 and enable it instantly. Its status is the initial status of the template, which is very convenient.


Let's calculate the total overhead:

Template (10 Gb)
In the future, each virtual machine only needs 4 GB or so, so that many virtual machines can be created. No installation is required, which greatly saves space.


Conclusion:

Let's try it out.








How to Create snapshots in a virtual machine

Three buttons: Create a snapshot, restore a snapshot, and manage a snapshot. Very simple.
 
How to Use vmwarevm snapshots?

A snapshot can hold your system in a certain state! The 1st button is used to create a snapshot. The 2nd button is used to return to the current snapshot. The 3rd button is used to manage all your snapshots.