[BROOKLYN-579] Add DNS TTL configuration via envvar #121
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| @@ -85,6 +89,9 @@ export EXTRA_JAVA_OPTS="-Dbrooklyn.location.localhost.address=127.0.0.1 ${EXTRA_ | |||
| # Increase garbage collection, see https://issues.apache.org/jira/browse/BROOKLYN-375 | |||
| export EXTRA_JAVA_OPTS="-XX:SoftRefLRUPolicyMSPerMB=1 ${EXTRA_JAVA_OPTS}" | |||
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| # Set the DNS TTL for the JVM | |||
| export EXTRA_JAVA_OPTS="-Dsun.net.inetaddr.ttl=${DNS_TTL} ${EXTRA_JAVA_OPTS}" | |||
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It would be nicer not to use the sun private system property but I take your point about the other value being a security property. I had a look to see if Karaf would let us specify this somehow but I don't see a way to do that. (You can configure security providers but there doesn't seem to be an equivalent for security properties.)
At the least though I would add some comment here explaining the use of sun.net - even just copy the text from the description of this PR.
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@geomacy Indeed, it is annoying that we cannot control the networkaddress.cache.ttl directly hence why I went for the old sun.net.inetaddr.ttl property.
Good idea though, I'll add a comment
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@geomacy I added the comment, should be ok now. |
[BROOKLYN-579] Add DNS TTL configuration via envvar Before, java was not refreshing the DNS records, ever. This is due to the default `networkaddress.cache.ttl` set to `-1`, i.e. cache forever. This PR updates the system property `sun.net.inetaddr.ttl` to `60` by default. It uses `sun.net.inetaddr.ttl` because `networkaddress.cache.ttl` **is not** a system property. But this has the desirable effect (see: https://stackoverflow.com/a/17219327)
Before, java was not refreshing the DNS records, ever. This is due to the default
networkaddress.cache.ttlset to-1, i.e. cache forever.This PR updates the system property
sun.net.inetaddr.ttlto60by default. It usessun.net.inetaddr.ttlbecausenetworkaddress.cache.ttlis not a system property. But this has the desirable effect (see: https://stackoverflow.com/a/17219327)