Ubuntu 22.04离线自动安装流程优化及ubuntu-desktop包安装提速咨询

Hey there! I get that waiting 30+ minutes for an offline autoinstall is super frustrating—let’s walk through how to optimize this process based on your setup and configuration files.

First, Let’s Diagnose the Slowdown #

Your current approach copies the APT cache from your minimal media to the target system, but there are a few likely bottlenecks here:

• The cached packages might not include all dependencies for ubuntu-desktop, forcing APT to waste time retrying failed network requests (even offline, it’ll keep checking for missing packages).
• Using default apt-get install flags without tuning for offline environments or hardware resources leads to slow unpacking and configuration.
• Your VM’s resource allocation might be limiting parallel processing during installation.

Step-by-Step Optimizations #

1. Fix Offline Package Preparation (Replace Cache Copy with Local Repository) #

Instead of relying on a copied APT cache, create a complete offline package repository with all ubuntu-desktop dependencies upfront. This ensures APT has every file it needs locally, no network checks required.

Update your chroot_script.sh (Run on a network-connected Ubuntu 22.04 machine):

#!/bin/bash
# Run this on a networked Ubuntu 22.04 amd64 system to download all required packages
mkdir -p /tmp/offline-packages

# Mount your Ubuntu 22.04 minimal ISO as a base source
mount -o loop ubuntu-22.04-minimal.iso /mnt

# Configure APT to use the ISO + network to fetch all dependencies
cat > /tmp/sources.list << EOF
deb [trusted=yes] file:///mnt jammy main restricted
deb http://archive.ubuntu.com/ubuntu jammy universe multiverse
EOF

# Download ubuntu-desktop and ALL dependencies to your offline directory
apt-get -o Dir::Etc::SourcesList=/tmp/sources.list update
apt-get -y install --download-only -o Dir::Cache::Archives=/tmp/offline-packages ubuntu-desktop

# Cleanup
umount /mnt

After running this, copy the /tmp/offline-packages folder to your offline media (the same drive with your autoinstall files).

2. Optimize Your user-data Late Commands #

Update your autoinstall config to use the local offline repository instead of copying cache. This eliminates APT’s network retry delays and ensures all packages are available locally:

#cloud-config
autoinstall:
  version: 1
  locale: en_US.UTF-8
  keyboard:
    layout: us
  identity:
    hostname: user
    username: user
    password: crypted_password
  late-commands:
    # Create mount point for offline packages
    - mkdir -p /target/mnt/offline
    # Mount your offline media's packages directory (adjust path to match your setup)
    - mount /media/minimal/offline-packages /target/mnt/offline
    # Add local repository to APT sources
    - echo 'deb [trusted=yes] file:///mnt/offline ./' > /target/etc/apt/sources.list.d/local-offline.list
    # Refresh APT to recognize the local repo
    - curtin in-target --target /target -- apt-get update
    # Install ubuntu-desktop with offline-friendly flags
    - curtin in-target --target /target -- apt-get -yy --no-install-recommends --no-upgrade install ubuntu-desktop
    # Cleanup
    - curtin in-target --target /target -- umount /mnt/offline
    - rm /target/etc/apt/sources.list.d/local-offline.list

• --no-install-recommends: Skips non-essential recommended packages (cuts down on installation time; remove this if you need the full desktop suite).
• --no-upgrade: Prevents APT from trying to update packages (useless offline, saves time).

3. Tune Your VirtualBox VM for Speed #

Given your host hardware (8GB RAM, 256GB SSD) and VM specs, these tweaks will boost installation speed:

• Increase CPU Cores: In VirtualBox, go to VM Settings > System > Processor, and allocate 2–4 cores (your host can handle this easily). APT and dpkg will use parallel processing to unpack/configure packages faster.
• Enable Host I/O Cache: Go to VM Settings > Storage > Controller: SATA, check "Use Host I/O Cache" to leverage your host’s SSD speed.
• Move VM Disk to SSD: Ensure your VirtualBox virtual disk file is stored on your host’s SSD (not a slow HDD).
• Optimize dpkg Parallelism: Add this line to your late-commands before installing packages to let dpkg use multiple cores:

  - curtin in-target --target /target -- echo 'jobs=2' > /etc/dpkg/dpkg.cfg.d/02parallel
  

  Adjust jobs to match the number of CPU cores you allocated (e.g., jobs=4 for 4 cores).

Final Checks #

• Double-check that all .deb packages in your offline-packages folder are intact (no corrupted files).
• Verify your offline media is mounted correctly during autoinstall (the path /media/minimal should match your setup—adjust if needed).

Give these changes a shot, and you should see your installation time drop significantly. Let me know if you run into any hiccups!

备注：内容来源于stack exchange，提问作者rain89