Migrating zones to DNSControl

This document explains how to migrate (convert) DNS zones from other systems to DNSControl’s dnsconfig.js file.

This document assumes you have DNSControl set up and working on at least one zone. You should have a working dnsconfig.js file and creds.json file as explained in the Getting Started doc.

General advice

First, use the Getting Started doc so that you have a working dnsconfig.js with at least one domain.

We recommend migrating one zone at a time. Start with a small, non-critical, zone first to learn the process. Convert larger, more important, zones as you gain confidence.

Experience has taught us that the best way to migrate a zone is to create an exact duplicate first. That is, convert the old DNS records with no changes. It is tempting to clean up the data as you do the migration… removing that old CNAME that nobody uses any more, or adding an A record you discovered was missing. Resist that temptation. If you make any changes it will be difficult to tell which changes were intentional and which are mistakes. During the migration you will know you are done when dnscontrol preview says there are no changes needed. At that point it is safe to do any cleanups.

Create the first draft

Create the first draft of the D() statement either manually or automatically.

For a small domain you can probably create the D() statements by hand, possibly with your text editor’s search and replace functions. However, where’s the fun in that?

The convertzone tool can automate 90% of the conversion for you. It reads a BIND-style zone file or an OctoDNS-style YAML file and outputs a D() statement that is usually fairly complete. You may need to touch it up a bit.

The convertzone command is in the cmd/convertzone subdirectory. Build instructions are here.

If you do not use BIND already, most DNS providers will export your existing zone data to a file called the BIND zone file format.

For example, suppose you owned the foo.com domain and the zone file was in a file called old/zone.foo.com. This command will convert the file:

convertzone -out=dsl foo.com <old/zone.foo.com >first-draft.js

If you are converting an OctoDNS file, add the flag -in=octodns:

convertzone -in=octodns -out=dsl foo.com <config/foo.com.yaml >first-draft.js

Add the contents of first-draft.js to dnsconfig.js

Run dnscontrol preview and see if it finds any differences. Edit dnsconfig.js until dnscontrol preview shows no errors and no changes to be made. This means the conversion of your old DNS data is correct.

convertzone makes a guess at what to do with NS records. An NS record at the apex is turned into a NAMESERVER() call, the rest are left as NS(). You probably want to check each of them for correctness.

Resist the temptation to clean up and old, obsolete, records or to add anything new. Experience has shown that making changes at this time leads to unhappy surprises, and people will blame DNSControl. Of course, once dnscontrol preview runs cleanly, you can do any kind of cleanups you want. In fact, they should be easier to do now that you are using DNSControl!

If convertzone could have done a better job, please let us know!

Example workflow

Here is an example series of commands that would be used to convert a zone. Lines that start with # are comments.

# Note this command uses ">>" to append to dnsconfig.js.  Do
# not use ">" as that will erase the existing file.
convertzone -out=dsl foo.com <old/zone.foo.com >>dnsconfig.js
#
dnscontrol preview
vim dnsconfig.js
# (repeat these two commands until all warnings/errors are resolved)
#
# When everything is as you wish, push the changes live:
dnscontrol push
# (this should be a no-op)
#
# Make any changes you do desire:
vim dnsconfig.js
dnscontrol preview
# (repeat until all warnings/errors are resolved)
dnscontrol push