Use of pool servers reveals unacceptable crash rate in async DNS

Clark B. Wierda cbwierda at
Mon Jun 27 20:06:25 UTC 2016

On Mon, Jun 27, 2016 at 3:47 PM, Hal Murray <hmurray at> wrote:

> cbwierda at said:
> > How are pool entries added when the service decides it needs more?
> There is some background stuff that roughly says "need more?", and if so
> fires off the DNS lookup.
> > Would it be possible to leverage this code for adding all servers
> specified
> > by name?
> Probably not directly, but it wouldn't be hard for the server code to use
> more than one address if that was desired.  Maybe it should be "servers"
> rather than "server".  Do you have an example where that would be useful?
> If you don't have lots of servers, you probably don't want to switch to
> using
> "pool" since that path will probably keep banging away at the DNS looking
> for
> more servers.
I'm not looking to change the operation of the server or pool directive.

I was thinking of setting up associations using the DNS lookup code.  If
the mechanism for adding new pool servers was blocking on the DNS call but
asynchronous to the rest of the daemon, I was figuring to call the lookup
with the name provided by the server directive.  The only real difference
between a specified server and a pool server is that you don't delete the
specified server.

I'm definitely not looking to bang on DNS servers any more than I have to.

Clark B. Wierda
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