> ## Documentation Index
> Fetch the complete documentation index at: https://dpos.xdr.ooo/llms.txt
> Use this file to discover all available pages before exploring further.

# Prerequisites

> Pre-upgrade checks for the Mirror Server, DP snapshots, connectivity, credentials, and cluster configuration.

# Prerequisites

Complete these checks before preparing or executing a production DP upgrade.

## Mirror Server

Use a clean Ubuntu 24.04 LTS amd64 server with:

* 2 vCPU minimum; 4 vCPU recommended
* 4 GB RAM minimum; 8 GB recommended
* 100 GB total disk for the current artifact set
* a stable IPv4 address reachable by all target DPs
* outbound HTTPS to the current GitHub, R2, ACPS, and Ubuntu bootstrap destinations

The Mirror Server must be able to serve DP hosts over TCP 80.

## Credentials

Have the following available before Menu 2:

* ACPS username
* ACPS password
* common `aella` worker SSH password when DL/DA workers are configured

Do not place passwords or tokens into documentation, public tickets, or shell history unnecessarily.

## DP snapshots

Create a full hypervisor snapshot of **every DP VM** before the destructive upgrade.

The project does not provide supported OS or DP-runtime rollback commands. Snapshot restore is the recovery method when a destructive failure cannot be safely recovered in place.

## Choose the correct mode

Confirm the current DP OS state and select:

* **Full OS Upgrade + Phase 2** for supported DPs on Ubuntu 16.04
* **Phase 2 Only** for supported DPs already on Ubuntu 24.04

The current target is DP **6.6.0**.

## Cluster information

For DL/DA clusters, collect:

* DL worker management IPs
* DA worker management IPs
* common `aella` worker password
* normal master-to-worker connectivity

Do not include master IPs in the worker lists.

## Final pre-execution gate

Do not start DP-side commands until:

1. Configuration is saved
2. Download and Prepare completed
3. HTTP Distribution is enabled
4. Verify Upgrade Readiness reports `PASS`
5. Menu 7 commands were generated from the current configuration