nself dr

nself dr

Disaster recovery operations: drill, promote-standby, reconfigure-dns, rollback, fence.

Synopsis

nself dr <subcommand> [flags]

Description

nself dr runs disaster recovery procedures. It covers planned drills (cold-start a fresh VM from latest backup, region failover, data corruption rehearsal), promoting a warm standby to primary, rewriting DNS records to a new primary IP, rolling back a promotion, and fencing the cluster (Redis read-only flag) to prevent split-brain writes during failover.

dr drill is the primary verification command. With --scenario cold-start, it provisions a Hetzner VM via cloud-init, restores the latest backup, runs a smoke test, and tears down. --install-cron installs the monthly drill systemd timer (nself-dr-drill.timer). --render-cloud-init and --render-alerts print the templates the drill would use without executing.

dr promote-standby requires production confirmation unless --yes is passed. dr reconfigure-dns --ip <new-ip> updates DNS to point traffic at the new primary. dr rollback demotes the promoted standby and resyncs from the original primary. dr fence sets a read_only=true flag in Redis that the application layer must honor.

Subcommands

Name	Description
drill	Execute a DR drill
promote-standby	Promote warm standby to primary
reconfigure-dns	Update DNS records to point to new primary
rollback	Demote promoted standby and resync from original primary
fence	Set read-only flag in Redis for split-brain prevention

Flags

dr drill

Flag	Default	Description
--scenario	cold-start	Drill scenario: cold-start, region-failover, data-corruption
--dry-run	false	Preview only
--now	false	Run a full provision-restore-smoke-destroy drill immediately
--install-cron	false	Install the monthly drill systemd timer
--schedule	monthly	Drill cadence for --install-cron (only monthly supported)
--hetzner-project	""	Hetzner project name used for drill VM
--vm-type	cx22	Hetzner server type for drill VM
--ssh-key	/root/.config/nself/dr-key.pub	Public SSH key path injected into drill VM
--region	fsn1	Hetzner location for drill VM
--render-cloud-init	false	Print the cloud-init user-data template and exit
--render-alerts	false	Print the Prometheus DRDrillFailed rule and exit

dr promote-standby

Flag	Default	Description
--region	""	Target region for promotion
--yes	false	Skip confirmation

dr reconfigure-dns

Flag	Default	Description
--ip	""	New primary IP address (required)

Examples

# Dry-run a cold-start drill
nself dr drill --dry-run

# Run an actual cold-start drill now
sudo nself dr drill --now

# Install the monthly drill timer on the ops host
sudo nself dr drill --install-cron --hetzner-project camarata

# Print the cloud-init template that would be used
nself dr drill --render-cloud-init

# Promote the warm standby to primary in eu-west
nself dr promote-standby --region eu-west --yes

# Point DNS at the new primary IP
nself dr reconfigure-dns --ip 5.75.235.42

# Fence writes during a manual failover
nself dr fence

See Also

• cmd-backup: backup operations
• cmd-promote: environment promotion
• cmd-watchdog: self-healing watchdog
• Commands: full command index

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