certbot: certs/ links into /etc/letsencrypt, mounted at the same path; the backup follows them

C-A1, C-Q4, D-guide:258, :291, :722. certbot's live/<host>/*.pem are
relative links into ../../archive/<host>/ (eff-certbot docs, "Where are
my certificates?": point a server at them "or create symlinks"). The
guide had `ln -s /etc/letsencrypt/live/<host> certs` and the nginx
fragment mounted live/<host> alone: inside the container the links led
into a directory it did not have - postfix-config.sh's [ -f ] false, no
copy, Postfix without a certificate - and the panel's backup, reading
certs/ through /selfpost-deploy, skipped links silently.

Now certs/fullchain.pem and certs/privkey.pem are links to
/etc/letsencrypt/live/<host>/, and /etc/letsencrypt is mounted read-only
at the same path: a commented line in deploy/docker-compose.yml for the
Apache scenario, mounted in the nginx fragment (./nginx/certbot-etc). The
guide's steps add certbot's own commands for a server that is not root -
chmod 0755 live archive, chgrp 998 + chmod 0640 the key, which certbot
keeps on renewal - so the panel reads them (Health, backup). Postfix's
side follows links already ([ -f ], cp, cmp, openssl). The vhost comment
says the same. The backup table: links are followed by the panel's
backup; a stopped tar stores them as links unless -h (GNU tar).

internal/backup: addTree follows, for certs/ only, a link to a regular
file and archives that file under the link's name; a link to nothing
reachable is an error naming it and the mount.

Tests: TestCertsLinksAreFollowed (certs/ -> live/ -> archive/, the
archive holds the files; the tree gone, Check names the dangling link;
Linux). Stand (2026-10-15, make e2e, exit 0): the stand mounts
./letsencrypt at /etc/letsencrypt; new certbot_layout_followed puts a new
pair into letsencrypt/archive/, relative links in live/, absolute links
in certs/, recreates the container: 465 serves the new serial, Health
names no renewal waiting, and the full backup holds certs/*.pem as
regular files with the archive's bytes. go vet and go test ./... pass on
the server (24 packages); the Linux-only tests of this session run there
and pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -147,6 +147,17 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); version
   the next update; the second then failed, and with it that start or that
   report (nothing was damaged). Each update now holds the database from
   its start and checks the version again (assumptions D-S3).
+- **Certificates from certbot reach Postfix and the backup.** The guide had
+  `certs` linked to certbot's `live/<host>`, and the nginx fragment mounted
+  that directory; its files are links into `archive/`, which the container
+  did not have, so Postfix started without a certificate and a full backup
+  went without one. `certs/` now holds two links into `/etc/letsencrypt`,
+  which is mounted read-only at the same path (a commented line in
+  `docker-compose.yml`, mounted in the nginx fragment); the guide gives the
+  two commands certbot's documentation has for a server that is not root.
+  A full backup follows links under `certs/` and carries the files; a link
+  that leads nowhere stops it, named (assumptions C-A1, C-Q4). If you use
+  certbot this way, follow the guide's new "Reverse proxy" steps.
 - **Words for what happens to mail match Postfix's.** A message refused with
   a temporary error while the panel or the spam filter does not answer was
   called deferred, which in Postfix's words is mail waiting in its queue;

deploy/apache/selfpost-vhost.conf

@@ -7,11 +7,13 @@
 # add the SSLCertificateFile/SSLCertificateKeyFile directives and a :80 -> :443
 # redirect vhost, and renews in the background via its own timer. The resulting
 # PEM files land at
-# /etc/letsencrypt/live/mail.example.com/{fullchain,privkey}.pem on the host —
+# /etc/letsencrypt/live/mail.example.com/{fullchain,privkey}.pem on the host,
-# bind-mount that directory read-only into the SelfPost container (see
+# as links into ../../archive/. Link certs/fullchain.pem and certs/privkey.pem
-# ../docker-compose.yml, the `./certs:/etc/postfix/tls:ro` volume) so Postfix
+# to them and mount /etc/letsencrypt read-only at the same path (see
-# can present the very same certificate on 465/587. One certificate, two
+# ../docker-compose.yml and docs/guide.md, "Reverse proxy") so Postfix can
-# consumers — no separate cert just for the panel.
+# present the very same certificate on 465/587. Mounting live/mail.example.com
+# alone gives the container links into a directory it does not have. One
+# certificate, two consumers — no separate cert just for the panel.
 
 <VirtualHost *:443>
 	ServerName mail.example.com

deploy/docker-compose.yml

@@ -72,9 +72,15 @@ services:
       # certs/ are archived alongside /data (architecture.md § Persistence).
       - .:/selfpost-deploy:ro
       # Read-only: SelfPost only ever reads certificates, never manages them.
-      # Point this at wherever your reverse-proxy/certbot writes PEM files, e.g.
+      # ./certs holds fullchain.pem and privkey.pem: the files themselves, or
-      # /etc/letsencrypt on the host.
+      # links to where your reverse proxy's certbot keeps them.
       - ./certs:/etc/postfix/tls:ro
+      # With certbot on the host (docs/guide.md, "Reverse proxy", Apache):
+      # certs/ holds links into /etc/letsencrypt/live/, and certbot's live/
+      # files are themselves relative links into archive/ - so the whole
+      # directory is mounted, at the same path, for the links to lead
+      # somewhere inside the container. Uncomment it then.
+      # - /etc/letsencrypt:/etc/letsencrypt:ro
     ports:
       # 465 (smtps, primary) and optionally 587 (submission/STARTTLS) are
       # published directly — mail traffic bypasses Apache entirely, it only ever

deploy/nginx/docker-compose.nginx.yml

@@ -31,10 +31,13 @@ services:
     volumes: !override
       - ./data:/data
       - .:/selfpost-deploy:ro
-      # Same host directory certbot below writes into — plain bind mount, no
+      # certs/ holds two links, fullchain.pem and privkey.pem, to
-      # named volume, so the PEM files are as directly inspectable as in the
+      # /etc/letsencrypt/live/mail.example.com/ - a path inside the
-      # Apache scenario.
+      # container: certbot's directory below is mounted there whole, because
-      - ./nginx/certbot-etc/live/mail.example.com:/etc/postfix/tls:ro
+      # its live/ files are relative links into archive/ (mounting live/ alone
+      # left them pointing at nothing). docs/guide.md, "Reverse proxy", nginx.
+      - ./certs:/etc/postfix/tls:ro
+      - ./nginx/certbot-etc:/etc/letsencrypt:ro
 
   nginx:
     image: nginx:1.27

docs/audit-2026-10-12.md

@@ -1005,12 +1005,16 @@ those after it move up one patch number each.
    it; a test with two concurrent opens behind a held lock. - **Opus**
    *Done 2026-10-15:* the test fails without the fix exactly as the
    register said ("table settings already exists") and passes with it.
-- [ ] **Certificates from certbot** (C-A1, C-Q4, D-guide:258, :291, :722):
+- [x] **Certificates from certbot** (C-A1, C-Q4, D-guide:258, :291, :722):
    certbot's `live/` files are relative links into `archive/`, so mounting
    `live/<host>` alone, or linking `certs` to it, leaves Postfix without a
    certificate and the backup without it. The deploy fragments mount
    `/etc/letsencrypt` read-only and point the paths into it; the backup
    follows a link under `certs/` to a regular file. - **Opus**
+   *Done 2026-10-15:* `certs/` holds links into `/etc/letsencrypt/live/`,
+   mounted read-only at the same path; certbot's own `chmod 0755` and
+   `chgrp`/`chmod 0640` for a server that is not root (kept on renewal) let the
+   panel read them; no copying hook.
 - [ ] **The rest of what the sources contradict** (C-M7 `<pct>0</pct>`,
    C-E2 the e2e zone serial, C-D1 a release gate comparing the image's
    package versions with the ones cited, C-K8/K9 and the comments the

docs/guide.md

@@ -255,14 +255,14 @@ SelfPost isn't tied to a specific proxy; pick whichever fits your host:
 
 | Proxy | Where certs live | Fragment |
 |---|---|---|
-| **Apache** (default/recommended) | Host disk, via the certbot Apache plugin — PEM files ready to bind-mount, no extraction step. | [deploy/apache/selfpost-vhost.conf](../deploy/apache/selfpost-vhost.conf) |
+| **Apache** (default/recommended) | Host disk, via the certbot Apache plugin — `certs/` links to them, no extraction step. | [deploy/apache/selfpost-vhost.conf](../deploy/apache/selfpost-vhost.conf) |
-| nginx | Host disk, via a certbot sidecar container — same PEM-ready shape as Apache. | [deploy/nginx/](../deploy/nginx/) |
+| nginx | Host disk, via a certbot sidecar container — the same shape as Apache. | [deploy/nginx/](../deploy/nginx/) |
 | Caddy | Automatic ACME, zero extra containers — simplest, but its on-disk cert path is versioned internal layout, not a stable API; verify it for the Caddy version you run. | [deploy/caddy/](../deploy/caddy/) |
 | Traefik | Bundled inside `acme.json` — needs a small extraction script to produce standalone PEM files. | [deploy/traefik/](../deploy/traefik/) |
 
 Apache is the recommended default because the certbot Apache plugin already
-writes plain `fullchain.pem`/`privkey.pem` files to a predictable path with no
+keeps `fullchain.pem`/`privkey.pem` at a predictable path with no extra moving
-extra moving parts between "certificate issued" and "Postfix can read it."
+parts between "certificate issued" and "Postfix can read it."
 
 **The proxy needs no security configuration of its own.** The panel emits its
 own `Content-Security-Policy`, `Strict-Transport-Security`, `X-Frame-Options`,
@@ -276,7 +276,8 @@ reject every form submission as cross-origin — the log says so explicitly,
 printing the `Origin` and `Host` it compared.
 
 In every case the proxy terminates HTTPS for the panel; the resulting
-certificate must end up under `./certs` as `fullchain.pem` and `privkey.pem`.
+certificate must end up under `./certs` as `fullchain.pem` and `privkey.pem` —
+the files, or links that lead to them inside the container.
 
 **Apache (recommended, on the host).** Install Apache with `ssl`, `proxy`, and
 `proxy_http` enabled. Copy
@@ -288,10 +289,30 @@ then issue a certificate:
 sudo certbot --apache -d mail.example.com
 ```
 
-Point `./certs` at the PEM files certbot wrote (symlink is fine):
+Link the two files into `./certs` and let the container see what the links
+lead to. certbot's `live/` files are themselves relative links into
+`archive/` (certbot's documentation, "Where are my certificates?", advises
+pointing servers at them or linking to them), so the whole of
+`/etc/letsencrypt` is mounted, read-only and at the same path — uncomment that
+line in `docker-compose.yml`. Mounting `live/mail.example.com` alone, or
+linking `certs` to it, gives the container links into a directory it does not
+have: Postfix then starts without a certificate.
 
 ```sh
-ln -s /etc/letsencrypt/live/mail.example.com certs
+mkdir certs
+ln -s /etc/letsencrypt/live/mail.example.com/fullchain.pem certs/fullchain.pem
+ln -s /etc/letsencrypt/live/mail.example.com/privkey.pem certs/privkey.pem
+```
+
+The panel reads them as its own user (Health shows the certificate, a full
+backup carries both files), through the container's group 998. certbot's
+documentation gives the way for a server that is not root, and certbot keeps
+the key's group and mode at every renewal:
+
+```sh
+sudo chmod 0755 /etc/letsencrypt/live /etc/letsencrypt/archive
+sudo chgrp 998 /etc/letsencrypt/archive/mail.example.com/privkey*.pem
+sudo chmod 0640 /etc/letsencrypt/archive/mail.example.com/privkey*.pem
 ```
 
 **nginx (containerised).** From the `deploy/` directory, merge the nginx
@@ -306,8 +327,20 @@ docker compose -f docker-compose.yml -f nginx/docker-compose.nginx.yml up -d
 ```
 
 Edit [deploy/nginx/nginx.conf.example](../deploy/nginx/nginx.conf.example) and
-replace `mail.example.com` first. The fragment bind-mounts certbot's output into
+replace `mail.example.com` first. The fragment mounts certbot's directory into
-both nginx and SelfPost.
+both nginx and SelfPost, at `/etc/letsencrypt`; `./certs` holds two links to
+`/etc/letsencrypt/live/mail.example.com/` — a path that exists inside the
+container, not on the host — and the panel reads the key through group 998,
+as in the Apache case:
+
+```sh
+mkdir certs
+ln -s /etc/letsencrypt/live/mail.example.com/fullchain.pem certs/fullchain.pem
+ln -s /etc/letsencrypt/live/mail.example.com/privkey.pem certs/privkey.pem
+sudo chmod 0755 nginx/certbot-etc/live nginx/certbot-etc/archive
+sudo chgrp 998 nginx/certbot-etc/archive/mail.example.com/privkey*.pem
+sudo chmod 0640 nginx/certbot-etc/archive/mail.example.com/privkey*.pem
+```
 
 **Caddy (containerised, automatic ACME).** Edit
 [deploy/caddy/Caddyfile](../deploy/caddy/Caddyfile) and the `<hostname>` placeholders
@@ -654,10 +687,13 @@ both the panel and Postfix —
 chgrp 998 certs/privkey.pem && chmod 640 certs/privkey.pem
 ```
 
-— and have whatever renews the certificate do the same (a certbot deploy hook,
+— and have whatever renews the certificate do the same; certbot does it by
-for one). A key readable by root alone is enough for Postfix, but then the
+itself, keeping the group and mode of a key on renewal (with `certs/` as links
-panel refuses to make a backup and names the file: it does not hand over an
+into `/etc/letsencrypt`, the commands of "Reverse proxy" above give certbot's
-archive without the key.
+own files the group). A key readable by root alone is enough for Postfix, but
+then the panel refuses to make a backup and names the file: it does not hand
+over an archive without the key. Links under `certs/` are followed: the
+archive holds the files they lead to.
 
 **2. `selfpost-backup` CLI — while the container is running (no downtime).**
 The panel button and this command call the same code path: a consistent SQLite
@@ -719,7 +755,7 @@ methods avoid it by stopping first.
 | SQLite consistency | `VACUUM INTO` snapshot | Safe when stopped | Safe when stopped |
 | `data/log/` | Excluded | Included (optional exclude) | Included (optional exclude) |
 | Postfix queue | No | Yes | Yes |
-| `certs/` private key | Yes (the panel needs it readable by group 998) | Yes | No — deploy files separate |
+| `certs/` private key | Yes (the panel needs it readable by group 998; links are followed) | Yes when `certs/` holds the files; links are stored as links unless `tar -h` | No — deploy files separate |
 | `data/manifest.json` | Written (version stamp) | Absent | Absent |
 | Restore version check | Yes — must match image tag | No | No |
 | Post-restore *Resync* | Yes, on first boot | No | No |

docs/roadmap.md

@@ -42,7 +42,7 @@ in `git log` and [CHANGELOG.md](../CHANGELOG.md).
 | from-header-binding | Hold a message's `From:` header against the application that sends it | shipped `2.4.0` | 9/9 | [plans/from-header-binding.md](plans/from-header-binding.md) |
 | panel-redesign | Panel redesign (accepted mockups, design contract) | shipped `2.0.0` | 27/27 | [plans/panel-redesign.md](plans/panel-redesign.md) |
 | schema-squash | Squash SQLite migrations into a 2.x baseline | built in panel-redesign (stage 1) | — | [plans/panel-redesign.md](plans/panel-redesign.md) |
-| audit-2026-10-12 | Follow-ups of the 2026-10-12 full-tree code audit, seven stages | in progress (stage 0 shipped `2.4.2`, stages 1+2 `2.5.0`, 2b `2.5.1`; next stage 2c → `2.5.2`) | 43/81 | [audit-2026-10-12.md](audit-2026-10-12.md) |
+| audit-2026-10-12 | Follow-ups of the 2026-10-12 full-tree code audit, seven stages | in progress (stage 0 shipped `2.4.2`, stages 1+2 `2.5.0`, 2b `2.5.1`; next stage 2c → `2.5.2`) | 44/81 | [audit-2026-10-12.md](audit-2026-10-12.md) |
 
 **Recommended order** (not binding; owner, 2026-10-09: feature order follows
 development convenience): **panel-redesign** shipped as `2.0.0` (2026-10-11) and

internal/backup/backup.go

@@ -160,7 +160,7 @@ func Create(w io.Writer, p Params) error {
 		return err
 	}
 
-	if err := addTree(tw, p.DataDir, DataArchivePrefix, excludedFromArchive, skipQueue); err != nil {
+	if err := addTree(tw, p.DataDir, DataArchivePrefix, excludedFromArchive, skipQueue, false); err != nil {
 		return err
 	}
 
@@ -221,7 +221,7 @@ func Check(p Params) error {
 	if err := ValidateDeployRoot(p.DeployRoot); err != nil {
 		return err
 	}
-	if err := addTree(nil, p.DataDir, DataArchivePrefix, excludedFromArchive, skipQueue); err != nil {
+	if err := addTree(nil, p.DataDir, DataArchivePrefix, excludedFromArchive, skipQueue, false); err != nil {
 		return err
 	}
 	return addDeployFiles(nil, p.DeployRoot, nil)
@@ -267,7 +267,12 @@ func addDeployFiles(tw *tar.Writer, deployRoot string, onWarn func(string)) erro
 		}
 		return fmt.Errorf("backup: stat %s: %w", CertsDirName, err)
 	}
-	return addTree(tw, certsDir, CertsDirName+"/", nil, nil)
+	// certs/ may hold links rather than files: certbot's own advice is to
+	// point a server at its live/ files "(or create symlinks)", and those
+	// are links again, relative, into archive/ (eff-certbot docs, "Where are
+	// my certificates?"; assumptions C-Q4, C-A1). The archive carries the
+	// files they lead to, under the links' names.
+	return addTree(tw, certsDir, CertsDirName+"/", nil, nil, true)
 }
 
 // addTree walks root and adds every regular file (and directory, to preserve
@@ -275,8 +280,11 @@ func addDeployFiles(tw *tar.Writer, deployRoot string, onWarn func(string)) erro
 // When exclude is non-nil, top-level names relative to root are skipped; skip,
 // when non-nil, leaves out whatever it says. With a nil tw nothing is written:
 // every file is opened and closed, which is how Check finds what cannot be read.
-// Non-regular, non-directory entries (symlinks, sockets) are skipped.
+// Non-regular, non-directory entries (symlinks, sockets) are skipped - except,
-func addTree(tw *tar.Writer, root, archivePrefix string, exclude map[string]bool, skip skipFunc) error {
+// with follow, a symbolic link to a regular file, which is archived as that
+// file under the link's name; a link that leads nowhere this process can
+// reach is an error, as an unreadable file is.
+func addTree(tw *tar.Writer, root, archivePrefix string, exclude map[string]bool, skip skipFunc, follow bool) error {
 	return filepath.WalkDir(root, func(path string, d fs.DirEntry, err error) error {
 		if err != nil {
 			return err
@@ -330,6 +338,15 @@ func addTree(tw *tar.Writer, root, archivePrefix string, exclude map[string]bool
 				return nil
 			}
 			return err
+		case follow && info.Mode()&fs.ModeSymlink != 0:
+			target, err := os.Stat(path)
+			if err != nil {
+				return fmt.Errorf("backup: %s is a link to a file this container cannot reach - with certbot, /etc/letsencrypt is mounted at the same path (guide § Reverse proxy): %w", name, err)
+			}
+			if !target.Mode().IsRegular() {
+				return nil
+			}
+			return writeTarFile(tw, name, target.Mode().Perm(), path)
 		default:
 			return nil
 		}

internal/backup/backup_test.go

@@ -10,6 +10,7 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -310,3 +311,51 @@ func TestCheckReportsWhatCannotBeRead(t *testing.T) {
 		t.Fatal("Check passed with .env missing from the deploy root")
 	}
 }
+
+// certs/ as certbot's advice leaves it: links into live/, which are relative
+// links into archive/ (C-Q4). The archive holds the files, under the links'
+// names; a link to nothing reachable stops the backup, naming it.
+func TestCertsLinksAreFollowed(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("symbolic links need privileges on Windows; the container is Linux")
+	}
+	dataDir, dbPath, deployRoot := seedDataDir(t)
+	le := t.TempDir()
+	writeFile(t, filepath.Join(le, "archive", "mail.example.com", "fullchain1.pem"), "CERT FROM CERTBOT")
+	writeFile(t, filepath.Join(le, "archive", "mail.example.com", "privkey1.pem"), "KEY FROM CERTBOT")
+	live := filepath.Join(le, "live", "mail.example.com")
+	if err := os.MkdirAll(live, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	certs := filepath.Join(deployRoot, CertsDirName)
+	for _, f := range []string{"fullchain", "privkey"} {
+		if err := os.Symlink("../../archive/mail.example.com/"+f+"1.pem", filepath.Join(live, f+".pem")); err != nil {
+			t.Fatal(err)
+		}
+		os.Remove(filepath.Join(certs, f+".pem"))
+		if err := os.Symlink(filepath.Join(live, f+".pem"), filepath.Join(certs, f+".pem")); err != nil {
+			t.Fatal(err)
+		}
+	}
+	p := Params{DataDir: dataDir, DBPath: dbPath, Version: "1.2.3", DeployRoot: deployRoot}
+	if err := Check(p); err != nil {
+		t.Fatalf("Check: %v", err)
+	}
+	var buf bytes.Buffer
+	if err := Create(&buf, p); err != nil {
+		t.Fatalf("Create: %v", err)
+	}
+	files := readArchive(t, buf.Bytes())
+	if files[CertsDirName+"/fullchain.pem"] != "CERT FROM CERTBOT" || files[CertsDirName+"/privkey.pem"] != "KEY FROM CERTBOT" {
+		t.Fatalf("certs in the archive: %q, %q", files[CertsDirName+"/fullchain.pem"], files[CertsDirName+"/privkey.pem"])
+	}
+
+	// /etc/letsencrypt not mounted: the link leads nowhere.
+	if err := os.RemoveAll(le); err != nil {
+		t.Fatal(err)
+	}
+	err := Check(p)
+	if err == nil || !strings.Contains(err.Error(), "certs/fullchain.pem is a link to a file this container cannot reach") {
+		t.Fatalf("Check with a dangling link: %v", err)
+	}
+}

test/e2e/certbot_test.go

@@ -0,0 +1,103 @@
+package e2e
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+// testCertbotLayout: certs/ as the guide now has an operator leave it with
+// certbot - two links into /etc/letsencrypt/live/<host>/, whose files are
+// relative links into archive/ - and /etc/letsencrypt mounted at the same
+// path (compose.override.yml mounts the stage's ./letsencrypt there). Postfix
+// serves the certificate the links lead to, Health shows it with nothing
+// waiting, and a full backup carries the files, not the links (assumptions
+// C-A1, C-Q4). Until 2.5.2 the guide had certs/ linked to live/<host>, and
+// the container got links into a directory it did not have.
+func testCertbotLayout(t *testing.T, sc *scenario) {
+	le := filepath.Join(h.stageDir, "letsencrypt")
+	archive := filepath.Join(le, "archive", selfpostHostname)
+	live := filepath.Join(le, "live", selfpostHostname)
+	for _, d := range []string{archive, live} {
+		if err := os.MkdirAll(d, 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	// A new pair, so what is served afterwards can only have come through
+	// the links.
+	if err := writeSelfSignedCert(filepath.Join(archive, "fullchain1.pem"), filepath.Join(archive, "privkey1.pem")); err != nil {
+		t.Fatal(err)
+	}
+	certs := filepath.Join(h.stageDir, "certs")
+	for _, f := range []string{"fullchain", "privkey"} {
+		link := filepath.Join(live, f+".pem")
+		_ = os.Remove(link)
+		if err := os.Symlink("../../archive/"+selfpostHostname+"/"+f+"1.pem", link); err != nil {
+			t.Fatal(err)
+		}
+		mounted := filepath.Join(certs, f+".pem")
+		if err := os.Remove(mounted); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.Symlink("/etc/letsencrypt/live/"+selfpostHostname+"/"+f+".pem", mounted); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := h.recreateSelfpost(); err != nil {
+		t.Fatalf("recreate selfpost over certbot's layout: %v", err)
+	}
+	if err := waitForPanelReady(); err != nil {
+		t.Fatalf("%v\n%s", err, h.logs("selfpost"))
+	}
+	if err := waitForSMTPSReady(60 * time.Second); err != nil {
+		t.Fatalf("%v\n%s", err, h.logs("selfpost"))
+	}
+
+	want, err := fileSerial(filepath.Join(archive, "fullchain1.pem"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := servedSerial()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.Cmp(want) != 0 {
+		t.Fatalf("port 465 serves serial %s, want %s, the certificate certs/ links to", got, want)
+	}
+
+	_, body, err := sc.panel.get("/server/health")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(body, "<dt>Renewal expires</dt>") {
+		t.Fatalf("Health names a renewal waiting, but Postfix serves what certs/ leads to")
+	}
+
+	resp, archived, err := sc.panel.postForm("/server/backup", nil)
+	if err != nil || resp.StatusCode != 200 {
+		t.Fatalf("full backup over certbot's layout: %v, status %v\n%.600s", err, resp, archived)
+	}
+	dir := t.TempDir()
+	names, err := untar(dir, []byte(archived))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, f := range []string{"fullchain", "privkey"} {
+		name := "certs/" + f + ".pem"
+		if !names[name] {
+			t.Fatalf("the backup has no %s", name)
+		}
+		fi, err := os.Lstat(filepath.Join(dir, name))
+		if err != nil || !fi.Mode().IsRegular() {
+			t.Fatalf("%s in the backup: %v, %v; want the file, not a link", name, fi, err)
+		}
+		inBackup, _ := os.ReadFile(filepath.Join(dir, name))
+		original, _ := os.ReadFile(filepath.Join(archive, f+"1.pem"))
+		if !bytes.Equal(inBackup, original) {
+			t.Fatalf("%s in the backup is not the file certbot's link leads to", name)
+		}
+	}
+}

test/e2e/compose.override.yml

@@ -37,6 +37,12 @@ services:
         # unset. The suite checks the stamp (image_stamped_with_version).
         VERSION: ${SELFPOST_E2E_VERSION:-e2e}
     image: selfpost:e2e
+    volumes:
+      # Where certs/ links lead when it is laid out as the guide has it with
+      # certbot (certbot_layout_followed): certbot's directory, mounted at the
+      # same path as on a host. Empty until that test fills it. Added to the
+      # base file's volumes (a new target).
+      - ./letsencrypt:/etc/letsencrypt:ro
     environment:
       SELFPOST_HOSTNAME: mail.e2e.test
       # Plain HTTP panel for the test client — no reverse proxy in this stand.

test/e2e/main_test.go

@@ -370,6 +370,9 @@ func TestE2E(t *testing.T) {
 	run("full_backup_restore", func(t *testing.T) {
 		testFullBackupRestore(t, sc)
 	})
+	run("certbot_layout_followed", func(t *testing.T) {
+		testCertbotLayout(t, sc)
+	})
 	run("enable_port25_features", func(t *testing.T) {
 		testEnablePort25Features(t, sc)
 	})

test/e2e/stage.go

@@ -27,7 +27,7 @@ func prepareStage(s *stack) error {
 	if err := removeAllBestEffort(s.stageDir); err != nil {
 		return fmt.Errorf("clean stage dir: %w", err)
 	}
-	dirs := []string{"data", "certs", "dns-stage", "mail-stage"}
+	dirs := []string{"data", "certs", "letsencrypt", "dns-stage", "mail-stage"}
 	for _, d := range dirs {
 		if err := os.MkdirAll(filepath.Join(s.stageDir, d), 0o755); err != nil {
 			return fmt.Errorf("mkdir %s: %w", d, err)