如何配置Virt-Manager将快照存储至第四台远程服务器？

Got it, let's break this down into two practical approaches based on your needs—either saving snapshots directly to Server 4 as you create them, or syncing local snapshots over afterward. Both are straightforward to set up with Virt-Manager and standard Linux tools.

Approach 1: Store Snapshots Directly on Server 4 (Recommended for Real-Time Remote Storage) #

This method configures Virt-Manager to use a remote shared storage pool on Server 4, so snapshots go straight there without hitting local storage first.

Step 1: Set Up Shared Storage on Server 4 #

We'll use NFS (most common for Linux environments) as an example—SMB works too if you prefer that.

• On Server 4:

  1. Install NFS server: sudo apt install nfs-kernel-server (Debian/Ubuntu) or sudo dnf install nfs-utils (RHEL/CentOS/Fedora)
  2. Create a directory for snapshots: sudo mkdir -p /srv/vm-snapshots
  3. Edit the NFS exports file: sudo nano /etc/exports
     Add this line (replace 192.168.1.0/24 with your KVM hosts' subnet):

     /srv/vm-snapshots 192.168.1.0/24(rw,sync,no_root_squash)
     

  4. Restart NFS to apply changes: sudo systemctl restart nfs-server

• On each of your 3 KVM hosts:

  1. Install NFS client: sudo apt install nfs-common or sudo dnf install nfs-utils
  2. Create a local mount point: sudo mkdir -p /mnt/server4-snapshots
  3. Mount the remote NFS share: sudo mount -t nfs server4-ip:/srv/vm-snapshots /mnt/server4-snapshots
  4. Make the mount permanent (add to /etc/fstab):
     Edit /etc/fstab and add:

     server4-ip:/srv/vm-snapshots /mnt/server4-snapshots nfs defaults 0 0
     

     Test it with sudo mount -a to ensure no errors.

Step 2: Add the Remote Storage Pool to Virt-Manager #

1. Open Virt-Manager on your KVM host.
2. Go to Edit > Connection Details > Storage tab.
3. Click the + button (Add Pool) in the bottom left.
4. Name the pool (e.g., Server4-Snapshots), select Directory as the type, then click Forward.
5. For the Target Path, browse to /mnt/server4-snapshots and click Finish.

Step 3: Create Snapshots to the Remote Pool #

1. Open the virtual machine's details window.
2. Switch to the Snapshots tab.
3. Click the + button (Create Snapshot).
4. In the popup window, use the Storage dropdown to select your Server4-Snapshots pool.
5. Name your snapshot and click Finish—your snapshot will be saved directly to Server 4.

Approach 2: Sync Local Snapshots to Server 4 Automatically #

If you prefer keeping local snapshots as a backup and syncing them to Server 4 later, this method uses rsync and cron (or inotify for real-time sync).

Step 1: Set Up Passwordless SSH Access to Server 4 #

This lets your KVM hosts sync files without entering a password every time.

1. On each KVM host, generate an SSH key pair (press enter for all prompts):

   ssh-keygen -t ed25519
   

2. Copy the public key to Server 4 (replace user and server4-ip with your details):

   ssh-copy-id user@server4-ip
   

3. Test the connection to confirm it works without a password: ssh user@server4-ip

Step 2: Create a Sync Script #

1. Create a script file (e.g., sync-snapshots.sh) with the following content:

   #!/bin/bash
   # Local directory where Virt-Manager stores snapshots (default below—adjust if you use custom pools)
   LOCAL_SNAP_DIR="/var/lib/libvirt/images"
   # Remote directory on Server 4
   REMOTE_DIR="user@server4-ip:/srv/vm-snapshots"
   
   # Sync only snapshot files (qcow2 is the default format; adjust if you use raw)
   rsync -avz --delete --include='*.qcow2' --exclude='*' "$LOCAL_SNAP_DIR/" "$REMOTE_DIR"
   

2. Make the script executable: chmod +x sync-snapshots.sh

Step 3: Automate the Sync #

Option A: Scheduled Sync with Cron

1. Open your crontab editor: crontab -e
2. Add a line to run the script at your desired interval. For example, to sync every day at 2 AM:

   0 2 * * * /path/to/sync-snapshots.sh
   

   Save and exit—cron will handle the rest.

Option B: Real-Time Sync with Inotify

If you want snapshots to sync immediately after creation, use inotify-tools to monitor the local snapshot directory:

1. Install inotify-tools: sudo apt install inotify-tools or sudo dnf install inotify-tools
2. Modify your sync script to listen for file changes:

   #!/bin/bash
   LOCAL_SNAP_DIR="/var/lib/libvirt/images"
   REMOTE_DIR="user@server4-ip:/srv/vm-snapshots"
   
   # Listen for new/modified files and sync qcow2 snapshots
   inotifywait -m -e create -e modify "$LOCAL_SNAP_DIR" | while read dir event file; do
       if [[ $file == *.qcow2 ]]; then
           rsync -avz "$dir$file" "$REMOTE_DIR"
       fi
   done
   

3. Set the script to run on boot (using systemd):
   • Create a systemd service file: sudo nano /etc/systemd/system/sync-snapshots.service

     [Unit]
     Description=Sync KVM snapshots to Server 4
     After=network.target
     
     [Service]
     User=root
     ExecStart=/path/to/sync-snapshots.sh
     Restart=always
     
     [Install]
     WantedBy=multi-user.target
     

   • Enable and start the service:

     sudo systemctl daemon-reload
     sudo systemctl enable --now sync-snapshots.service
     

Quick Notes #

• Make sure Server 4 has enough storage space—snapshots can be nearly as large as your VM disks, especially if you use full snapshots.
• For NFS, ensure your network is stable; a dropped connection during snapshot creation can corrupt the file.
• If you use SMB instead of NFS, adjust the mount command on KVM hosts to:

  sudo mount -t cifs //server4-ip/snapshots /mnt/server4-snapshots -o username=your-user,password=your-pass
  

内容的提问来源于stack exchange，提问作者xav