Repository Setup

restic Repository Setup (Cloudflare R2 / S3)

Create the encryption password, wire up the storage credentials, and initialize the repository. restic always encrypts client-side (AES-256) — the password is the only key; lose it and the backup is permanently unrecoverable. R2 server-side encryption is redundant here.

Step 1 — Encryption password

install -d -m700 /root/.restic
openssl rand -base64 48 > /root/.restic/password   # strong random key
chmod 600 /root/.restic/password

STOP — copy this password off the server right now (password manager / vault). Without it, none of the backups can ever be restored. This is the single most important action in the whole setup.

Step 2 — Storage credentials env file

Write /root/.restic/r2.env (mode 600). For Cloudflare R2:

cat > /root/.restic/r2.env <<'EOF'
AWS_ACCESS_KEY_ID=<R2 access key id>
AWS_SECRET_ACCESS_KEY=<R2 secret access key>
AWS_DEFAULT_REGION=auto
RESTIC_REPOSITORY=s3:https://<account_id>.r2.cloudflarestorage.com/<bucket>
RESTIC_PASSWORD_FILE=/root/.restic/password
RESTIC_COMPRESSION=auto
EOF
chmod 600 /root/.restic/r2.env

• Repository URL form: s3:https://<account_id>.r2.cloudflarestorage.com/<bucket> — note the s3: prefix in front of the full https:// endpoint.
• AWS_DEFAULT_REGION=auto is required for R2 (or pass -o s3.region=auto). Standard AWS region names do not work.
• Other S3-compatible providers: same shape, e.g. Wasabi s3:https://s3.<region>.wasabisys.com/<bucket>, MinIO s3:http://host:9000/<bucket>, AWS s3:s3.amazonaws.com/<bucket> (+ real region).

Sourcing for any manual restic command:

set -a; . /root/.restic/r2.env; set +a

Step 3 — Initialize and verify

set -a; . /root/.restic/r2.env; set +a

# IDEMPOTENCY: never re-init over an existing repo. Check first.
if restic cat config >/dev/null 2>&1; then
  echo "Repository already exists — do NOT re-init (would not overwrite, but never regenerate the password)."
else
  restic init           # creates the encrypted repo
fi

restic cat config       # readable config => keys + password work; expect "version":2

"version":2 confirms repository format v2 — compression is active. If it shows v1 (older binary created it), upgrade in place: restic migrate upgrade_repo_v2.

R2 API token requirements

The R2 API token must have:

• Object Read & Write permission
• a scope that includes this bucket (or all buckets in the account)
• the bucket must exist in the same account whose account_id is in the endpoint

Troubleshooting init (AccessDenied / connection)

Fix R2 tokens in the Cloudflare dashboard → R2 → Manage R2 API Tokens.

R2 cost & lifecycle

• R2 has zero egress fees; you pay for storage + Class A/B operations. restic's pack format keeps operation counts reasonable.
• CRITICAL — never set a bucket lifecycle rule that deletes or expires objects. restic owns retention via forget --prune (see backup-script); any external deletion corrupts the repository. A lifecycle rule that only aborts incomplete multipart uploads is safe and recommended.

Encryption at rest

restic encrypts everything client-side before upload, so the objects in R2 are already ciphertext. Enabling R2/S3 SSE on top is harmless but redundant — it does not protect you if the restic password is lost.

Gotchas

• Password loss = total, unrecoverable loss. Force an off-server copy before init.
• Idempotency: check restic cat config before init; never regenerate the password over an existing repo — you'd lose access to every prior snapshot.
• Both /root/.restic/password and /root/.restic/r2.env must be mode 600, root-owned. Never commit r2.env to git.
• Repo format v2 / compression needs restic ≥ 0.14 (see setup).

What this skill does NOT cover

• Choosing what to back up → discover-backup-sources
• The backup script and retention → backup-script
• Restoring → disaster-recovery