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chore: change DNS record TTL from 10 minutes to 2 seconds #70

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Merged
merged 3 commits into from
Apr 10, 2025
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chore: change DNS record TTL from 10 minutes to 2 seconds #70

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chore: change DNS record TTL from 10 minutes to 2 seconds
ethanndickson Apr 9, 2025
0873ee9
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ethanndickson Apr 9, 2025
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ethanndickson Apr 9, 2025
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5 changes: 4 additions & 1 deletion net/dns/resolver/tsdns.go
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Expand Up @@ -45,7 +45,10 @@ const dnsSymbolicFQDN = "magicdns.localhost-tailscale-daemon."
const maxResponseBytes = 4095

// defaultTTL is the TTL of all responses from Resolver.
const defaultTTL = 600 * time.Second
// Coder: We've changed this from 10 minutes to 2 seconds, as we'd like to use
// the existence of Coder Connect DNS records to determine whether Coder Connect
// is running.
const defaultTTL = 2 * time.Second
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@deansheather deansheather Apr 9, 2025

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10 seconds sounds better to me. The only time that records will conflict will be during a restart of a workspace, which I would guess takes 20-30 seconds in the fastest possible template.

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@spikecurtis spikecurtis Apr 9, 2025

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We aren't just worried about records with conflicting IP addresses, we are worried about turning off Coder Connect entirely and then using some other tool to connect to the workspace, and having the OS return a stale record indicating that Coder Connect is running when it isn't.

So, the relevant time scale is how quickly a human can turn off Coder Connect and then switch to another tool, not a workspace restart.


var (
errNotQuery = errors.New("not a DNS query")
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