After upgrading my Ubuntu from 32-bit to 64-bit, I encountered a frustrating situation where Vagrant (v1.6.3) running on VirtualBox (v4.3.14) kept throwing the "not ready for SSH" error across all my boxes - including both Laravel Homestead and the standard precise32 box.

The error manifests when running vagrant ssh-config:

The provider for this Vagrant-managed machine is reporting that it
is not yet ready for SSH. Depending on your provider this can carry
different meanings. Make sure your machine is created and running and
try again.

The VM gets stuck during the boot process:

==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2201
default: SSH username: vagrant
default: SSH auth method: private key

First, let's verify some fundamentals:

# Check VirtualBox guest additions version
vboxmanage guestproperty get "vmname" "/VirtualBox/GuestAdd/Version"

# Verify Vagrant box status
vagrant global-status

# Check SSH configuration
vagrant ssh-config --debug

For Ubuntu 14.04 64-bit systems, these solutions worked consistently:

# 1. Reinstall VirtualBox with proper kernel modules
sudo apt-get remove --purge virtualbox*
sudo apt-get install virtualbox-4.3

# 2. Rebuild kernel modules
sudo /etc/init.d/vboxdrv setup

# 3. Update Vagrant plugins
vagrant plugin update

# 4. For Laravel Homestead specifically
homestead destroy && homestead up

When standard SSH fails, try direct connection through VirtualBox:

# Find the VM name
vboxmanage list vms

# Start in headless mode
vboxmanage startvm "vmname" --type headless

# Then attempt SSH manually
ssh -p 2201 -i ~/.vagrant.d/insecure_private_key vagrant@127.0.0.1

Modify your Vagrantfile with these settings:

config.vm.provider "virtualbox" do |vb|
  vb.gui = true  # Enable GUI to see boot errors
  vb.customize ["modifyvm", :id, "--vram", "16"]  # Fix graphics issues
  vb.customize ["modifyvm", :id, "--ioapic", "on"]  # For 64-bit systems
end

config.ssh.insert_key = false  # Preserve default insecure key
config.ssh.private_key_path = "~/.vagrant.d/insecure_private_key"

Network configuration problems often cause SSH readiness failures. Check these:

# Inside the VM (access via VirtualBox console)
sudo service networking restart
sudo ifconfig -a
sudo route -n

# On host machine
vboxmanage showvminfo "vmname" | grep NIC
vagrant reload --provision

The nuclear option that often works:

# Completely clean the environment
vagrant destroy
rm -rf .vagrant
vagrant box update
vagrant up

---

When working with Vagrant (v1.6.3), VirtualBox (v4.3.14) and Ubuntu 14.04 LTS 64-bit environments, you might encounter this frustrating SSH connection issue. The error typically manifests in two ways:

# Through ssh-config command
$ vagrant ssh-config
The provider for this Vagrant-managed machine is reporting that it
is not yet ready for SSH...

# During vagrant up process
==> default: Waiting for machine to boot. This may take a few minutes...
default: SSH address: 127.0.0.1:2201
default: SSH username: vagrant
default: SSH auth method: private key

The problem appears specifically after upgrading from 32-bit to 64-bit Ubuntu systems. Several important facts emerge:

• SSH keys are properly configured and were working previously
• The issue affects multiple boxes (including Laravel Homestead and precise32)
• Complete reinstallation didn't resolve the problem

Here's a step-by-step method to diagnose and resolve the issue:

# First check the VM status
$ vagrant status
Current machine states:
default                   running (virtualbox)

# Verify VirtualBox VM directly
$ VBoxManage list runningvms
"homestead_default_123456789" {uuid}

# Check network configuration
$ vagrant ssh-config --debug
[output will show detailed connection attempts]

Case 1: Boot Timeout Issues

Modify your Vagrantfile with these settings:

config.vm.boot_timeout = 600
config.vm.provider "virtualbox" do |vb|
  vb.gui = true  # Enable GUI to see boot process
end

Case 2: SSH Key Authentication Problems

Manually verify SSH connectivity:

$ ssh -vvv -i ~/.vagrant.d/insecure_private_key vagrant@127.0.0.1 -p 2201
# Check output for authentication details

For persistent cases, enable detailed logging:

$ export VAGRANT_LOG=debug
$ vagrant up &> vagrant_debug.log

Common findings in logs might include:

• Network interface initialization failures
• VirtualBox guest additions version mismatches
• Filesystem mounting issues

To avoid similar issues in the future:

# Keep components updated
$ vagrant plugin update
$ sudo apt-get update && sudo apt-get upgrade virtualbox

# Maintain clean box environments
$ vagrant box update
$ vagrant box prune

Remember that VirtualBox 4.3.x has known networking issues with newer Linux kernels. Consider upgrading to VirtualBox 5.0+ if possible.