erwin/docker-nsupdate-ddns
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Fixed config loading, added Dockerfile

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Merijntje Tak
2022-07-10 16:34:53 +02:00
parent 6e8bf94005
commit 5909c88c08
9 changed files with 128 additions and 42 deletions
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35
README.md
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@@ -1,6 +1,6 @@
# docker-nsupdate-ddns
This script pushes container/ip information from a Docker instance to a DNS server via the DNS update mechanism desribed in RFC 2136 (nsupdate). nsupdate is implemented by ISC Bind9.
This script pushes container/ip information from local Docker instance to a DNS server via the DNS update mechanism desribed in RFC 2136 (nsupdate). nsupdate is implemented by ISC Bind9.
Every REFRESH_INTERVAL seconds, it queries all the Docker containers on the local host, finds their IP and pushes it with the name to the DNS server.
@@ -13,22 +13,25 @@ The names of the environment variables is the same as in the config file. Enviro
### Environment variables
```bash
docker run -d \
-v /var/run/docker.sock:/var/run/docker.sock \
-e DOCKER_SOCKET=/var/run/docker.sock \
-e DOMAIN=int.mtak.nl \
-e HOSTNAME_LABEL=nl.mtak.docker-bind-ddns.hostname \
-e HOSTNAME_LABEL=nl.mtak.docker-nsupdate-ddns.hostname \
-e DEFAULT_NETWORK=10.100.0.192/26 \
-e REFRESH_INTERVAL=5 \
-e ONE_SHOT=True \
-e NAMESERVER=10.100.0.11 \
-e TSIG_NAME=dck1 \
-e TSIG_KEY=SyYXDCJ4kIs3qhvI= \
merijntjetak/docker-bind/ddns:latest
merijntjetak/docker-nsupdate-ddns:latest
```
### Config file
```bash
cat <<EOF >configfile
DOCKER_SOCKET=/var/run/docker.sock
DOMAIN=int.mtak.nl
HOSTNAME_LABEL=nl.mtak.docker-bind-ddns.hostname
HOSTNAME_LABEL=nl.mtak.docker-nsupdate-ddns.hostname
DEFAULT_NETWORK=10.100.0.192/26
REFRESH_INTERVAL=5
ONE_SHOT=True
@@ -38,15 +41,17 @@ TSIG_KEY=SyYXDCJ4kIs3qhvI=
EOF
docker run -d \
-v `pwd`/configfile:/configfile
merijntjetak/docker-bind-ddns:latest /configfile
-v `pwd`/configfile:/configfile \
-v /var/run/docker.sock:/var/run/docker.sock \
merijntjetak/docker-nsupdate-ddns:latest /configfile
```
### Configuration
- `DOCKER_SOCKET` - Sets the location of the Docker socket
- `DOMAIN` - Sets the domain in which the records are created. Needs to match the Bind zone.
- `HOSTNAME_LABEL` - Docker label to override the default record name with. Use with `docker --label=nl.mtak.docker-bind-ddns.hostname=nginx` to get `nginx.int.mtak.nl`
- `HOSTNAME_LABEL` - Docker label to override the default record name with. Use with `docker --label=nl.mtak.docker-nsupdate-ddns.hostname=nginx` to get `nginx.int.mtak.nl`
- `DEFAULT_NETWORK` - Preferred network to find IP for, in case there are multiple networks
- `REFRESH_INTERVAL` - Interval between updates
- `ONE_SHOT` - Set to True for the script to update once and immediately quit (nice for debugging)
@@ -79,18 +84,17 @@ docker run -d \
## Design
### Requirements
- Eventual redunancy (Bind9 zone transfers to secondary)
- Support for multiple individual Docker servers
- IPv6 support
- Detect hostname in decreasing order of priority:
- [x] Eventual redundancy (Bind9 zone transfers to secondary)
- [x] Support for multiple individual Docker servers
- [ ]IPv6 support
- [x]Detect hostname in decreasing order of priority:
- label
- Container name
- Forward-only
- Clean up DNS (DNS is stateful but the script isn't, so there might be a mismatch)
- [x]Forward-only
- [ ]Clean up DNS (DNS is stateful but the script isn't, so there might be a mismatch)
### Todo
### Nice to have
- Make event-driven with [Ahab](https://github.com/instacart/ahab)
- Add tests
### Alternatives
@@ -98,3 +102,4 @@ docker run -d \
CoreDNS didn't fit the requirements, because zone transfers out of a CoreDNS server do not
include the records from the coredns-dockerdiscovery plugin.
K3s and k8s would probably do this, but incur significant complexity over a standalone Docker instance.