Hetzner: cpx (new gen) defaults + capacity-aware placement#166
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barnabasbusa wants to merge 5 commits intomasterfrom
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Hetzner: cpx (new gen) defaults + capacity-aware placement#166barnabasbusa wants to merge 5 commits intomasterfrom
barnabasbusa wants to merge 5 commits intomasterfrom
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ARM cax* capacity at Hetzner has been chronically tight across all EU locations, causing repeated `resource_unavailable` placement failures on apply. Switch the supernode/fullnode defaults to the spec-equivalent AMD shared-vCPU sizes which have far better availability: - supernode: cax41 (16/32) -> cpx51 (16/32) - fullnode: cax31 (8/16) -> cpx41 (8/16) The arch label logic already keys off the `^cax` regex, so labels will automatically flip to `arch:amd64`.
Hetzner is rolling out a new CX line that replaces the CPX series in many locations. CPX SKUs (cpx41/cpx51) are no longer creatable in fsn1/nbg1/hel1, returning `unsupported location for server type (invalid_input)` from the API. Switch defaults to the new CX equivalents at identical specs and slightly lower price: - supernode: cpx51 (16/32) -> cx53 (16/32) — €31.99 -> €22.99 - fullnode: cpx41 (8/16) -> cx43 (8/16) — €24.49 -> €12.49
barnabasbusa
changed the title
Hetzner ARM (cax*) capacity has been chronically tight in EU and
the legacy CPX line (cpx41/cpx51) is no longer creatable in some
regions. Newer cpx42/cpx62 are widely available and still ~3-4x
cheaper than DigitalOcean for equivalent specs.
Two behavior changes layered together:
1. Default sizes flipped to the new-gen CPX:
- supernode: cpx62 (16 vCPU / 32 GB / 640 GB)
- fullnode: cpx42 (8 vCPU / 16 GB / 320 GB)
2. Capacity-aware placement: query `hcloud_datacenters` and
`hcloud_server_type` data sources at plan time, build the set
of locations whose datacenters currently report both SKUs as
`available`, and round-robin only across those. Falls back to
the full region list if every region is sold out.
- `lifecycle { ignore_changes = [location] }` keeps existing
servers pinned where they were placed even if next plan's
filter would prefer a different region (location is
replacement-forced otherwise).
- `hcloud_server_network` reads the actual server location
post-state so the network reference stays correct after any
drift between planned and real location.
Arch labels still flip to `arch:amd64` automatically via the
existing `^cax` regex.
barnabasbusa
changed the title
Capture why we landed on cpx42/cpx62 (capacity vs cax/legacy cpx, cost vs DigitalOcean) so future operators don't have to relitigate the choice.
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Summary
Two changes layered together to address recurring
resource_unavailableandunsupported location for server typeerrors onterraform apply:1. New default SKUs
cax41(16 ARM / 32 GB / 320 GB)cpx62(16 AMD / 32 GB / 640 GB)cax31(8 ARM / 16 GB / 160 GB)cpx42(8 AMD / 16 GB / 320 GB)Hetzner ARM
cax*capacity has been chronically tight, and the legacycpx41/cpx51SKUs are no longer creatable in some EU locations. The new-gencpx42/cpx62are widely available.Cost vs DigitalOcean
cpx*is more expensive thancax*/cx*, but still dramatically cheaper than DigitalOcean for equivalent specs:cpx42≈ €25/mos-8vcpu-16gb≈ €88/mo (~$96)cpx62≈ €50/mos-16vcpu-32gb≈ €177/mo (~$192)So we're roughly 3–4× cheaper than DO while staying on a SKU that's actually in stock. For a multi-month devnet that's hundreds of euros saved per supernode.
The arch label logic at
hetzner.tfalready keys off the^caxregex, so labels automatically flip toarch:amd64.2. Capacity-aware placement
At every plan/apply, query
hcloud_datacentersandhcloud_server_typedata sources, build the set of locations whose datacenters currently report both SKUs asavailable, and round-robin new servers only across those. Falls back to the fullvar.hetzner_regionslist if every region is sold out (so plan doesn't error out — at that point you're stuck either way).lifecycle { ignore_changes = [location] }onhcloud_serverkeeps existing placements pinned even if next plan's filter would prefer a different region (location is replacement-forced onhcloud_serverotherwise).hcloud_server_networknow readshcloud_server.main[each.key].location(the actual post-state location) so the network reference stays correct under any drift.Test plan
resource_unavailable/unsupported locationerrorsecho 'local.hetzner_available_locations' | terraform consolereturns the expected non-empty list when capacity is healthy