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Files

Miek Gieben 3a0c7c6153 plugin/file: load secondary zones lazily on startup (#2944 )

This fixes a long standing bug:
fixes: #1609

Load secondary zones in a go-routine; this required another mutex to
protect some fields; I think those were needded anyway because a
transfer can also happen when we're running; we just didn't have a test
for that situation.

The test had to be changed to wait for the transfer to happen at this is
async now.

Signed-off-by: Miek Gieben <miek@miek.nl>

2019-06-30 05:22:34 +08:00

log_test.go

Clean up tests logging (#1979 )

2018-07-19 16:23:06 +01:00

OWNERS

Add OWNERS file (#1486 )

2018-02-08 10:55:51 +00:00

README.md

Default to upstream to self (#2436 )

2019-01-13 16:54:49 +00:00

secondary.go

Remove the word middleware (#1067 )

2017-09-14 09:36:06 +01:00

setup_test.go

Remove the word middleware (#1067 )

2017-09-14 09:36:06 +01:00

setup.go

plugin/file: load secondary zones lazily on startup (#2944 )

2019-06-30 05:22:34 +08:00

README.md

secondary

Name

secondary - enables serving a zone retrieved from a primary server.

Description

With secondary you can transfer (via AXFR) a zone from another server. The retrieved zone is not committed to disk (a violation of the RFC). This means restarting CoreDNS will cause it to retrieve all secondary zones.

secondary [ZONES...]

ZONES zones it should be authoritative for. If empty, the zones from the configuration block are used. Note that without a remote address to get the zone from, the above is not that useful.

A working syntax would be:

secondary [zones...] {
    transfer from ADDRESS
    transfer to ADDRESS
    upstream
}

transfer from specifies from which address to fetch the zone. It can be specified multiple times; if one does not work, another will be tried.
transfer to can be enabled to allow this secondary zone to be transferred again.
upstream resolve external names found (think CNAMEs) pointing to external names. This is only really useful when CoreDNS is configured as a proxy; for normal authoritative serving you don't need or want to use this. CoreDNS will resolve CNAMEs against itself.

When a zone is due to be refreshed (Refresh timer fires) a random jitter of 5 seconds is applied, before fetching. In the case of retry this will be 2 seconds. If there are any errors during the transfer the transfer fails; this will be logged.

Examples

Transfer example.org from 10.0.1.1, and if that fails try 10.1.2.1.

example.org {
    secondary {
        transfer from 10.0.1.1
        transfer from 10.1.2.1
    }
}

Or re-export the retrieved zone to other secondaries.

. {
    secondary example.net {
        transfer from 10.1.2.1
        transfer to *
    }
}

Bugs

Only AXFR is supported and the retrieved zone is not committed to disk.