Gabriel Radureau e6fc24c101 fix(dns): harden DNS resilience after power-cut incident
During the 2026-04-13 power cut recovery, DNS resolution failures blocked
Longhorn reinstall. Root causes:
- CoreDNS forwarded to a single hardcoded Pi-hole IP instead of both HA instances
- CoreDNS main Corefile forwarded to /etc/resolv.conf which pointed to itself on pi3
- Pi-hole lacked explicit upstream DNS, relying on DHCP-provided config
- dnsmasq system service conflicted with pihole-FTL on port 53

Changes:
- k3s_dns: forward CoreDNS to both Pi-hole HA instances (pi1 + pi3) dynamically
- k3s_dns: update main CoreDNS Corefile to forward to Pi-holes instead of resolv.conf
- pihole defaults: add explicit upstream DNS servers (8.8.8.8, 1.1.1.1, 8.8.4.4)
- pihole ha_setup: write /etc/dnsmasq.d/99-upstream.conf with explicit upstreams
- rpi: add dnsmasq user to dip group and disable conflicting dnsmasq service on Pi-hole nodes

See docs/adr/20260414-internal-dns-architecture.md for full rationale.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-14 10:54:42 +02:00
2026-01-02 18:17:53 +01:00
2024-12-15 22:13:03 +01:00

Arcodange Factory

%%{init: { 'logLevel': 'debug', 'theme': 'base', 'rough':true } }%%
flowchart

    prepare_hd>HD setup]
    prepare_pg>PG Setup]
    prepare_gitea>Gitea Setup]

    origin_repo[[original repositories]]
    github_repo_m[[gitea mirrors]]
    gitlab_repo_m[[gitea mirrors]]

    origin_repo -. mirrored .->gitlab_repo_m
    origin_repo -. mirrored .->github_repo_m

    tofu.state -. manages providers/go-gitea .- origin_repo
    tofu.state -. manages providers/gitlabhq/gitlab .- gitlab_repo_m
    tofu.state -. manages providers/integrations/github .- github_repo_m

    subgraph Home
        subgraph pi1
            runner[/gitea runners\]
            subgraph small HD
                backup_data
            end
        end
        subgraph pi2
            PG[(Postgres)]
            subgraph Gitea
                origin_repo
            end
            subgraph HD
                PG_data
                Gitea_data
            end
        end
        subgraph pi3
            subgraph ai
                ollama
            end
        end
        subgraph "master (macbook pro)"
            ansible{{ansible control-node}}
            tofu{{opentofu control-node}}
            subgraph ansible_scripts
                direction TB
                prepare_hd --> prepare_pg --> prepare_gitea
            end
        end
    end
    subgraph Internet
        subgraph Gitlab
            subgraph Group Arcodange
                gitlab_repo_m
            end
        end
        subgraph Github
            subgraph Organization Arcodange
                github_repo_m
            end
        end
        subgraph GCP
            subgraph project arcodange
                subgraph gs://arcodange-tf
                    tofu.state
                end
            end
        end
    end

    tofu == plan/apply ==> tofu.state
    ansible == deploy ==> HD
    ansible == deploy ==> PG
    ansible == deploy ==> Gitea
    ansible --- ansible_scripts

classDef done fill:gold,stroke:indigo,stroke-width:4px,color:blue;
class prepare_hd,nodeId2 done;

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