I am using NFSv4 on Ubuntu 20.04 and 24.04 filesystems.
I cannot understand how to use idmapd.conf. I have read the man page, multiple Stack Exchange posts, and multiple blogs, and none of them explain the basic concepts well enough for me to apply them to my situation. I have probably a dozen or more questions, which I'll post individually.
In this scenario, I have three computers. The first is Exporter; it's the machine that will export the NFS filesystem. Its FQDN is exporter.example.com.
The other two are Recipient1 and Recipient2. Each of these will mount the exported filesystem. They have the same set of users, but different UIDs and GIDs assigned to them. In particular, both have a user (with group) 'figaro' who should be the owner and group owner of the mounted filesystem. Their FQDNs are recipient1.example.com and recipient2.example.com, respectively.
The choice of the Domain variable appears to be arbitrary as long as it matches among all three systems. I'll use nfs4data.
The "Static" mapping system seems simplest, so I'll try that first. As far as I can piece together, the mapping scheme works by identifying a "universal" username and then configuring each system to recognize that universal username as a specific one of its users. I'll use dataowner@nfs4data as the universal username.
The three /etc/idmapd.conf files are then
# Exporter
[General]
Domain = nfs4data
[Translation]
Method = static
[Static]
dataowner@nfs4data = {Exporter username}
# Recipient1
[General]
Domain = nfs4data
[Translation]
Method = static
[Static]
dataowner@nfs4data = figaro
# Recipient2
[General]
Domain = nfs4data
[Translation]
Method = static
[Static]
dataowner@nfs4data = figaro
Is this correct?
