The documentation describing how to connect to a kerberos secured endpoint shows the following:
curl -i --negotiate -u : "http://<HOST>:<PORT>/webhdfs/v1/<PATH>?op=..."
The -u
flag has to be provided but is ignored by curl.
Does the --negotiate
option cause curl to look for a keytab that was created beforehand with the kinit
command, or will curl prompt for credentials?
If it looks for a keytab file, what filename will the command be looking for?
Being a once-in-a-while-contributor to curl
in that area. Here is what you need to know:
curl(1)
itself knows nothing about Kerberos and will not interact neither with your credential cache nor your keytab file. It will delegate all calls to a GSS-API implementation which will do the magic for you. What magic depends on the library, Heimdal and MIT Kerberos.
Based on your question, I assume that you have little knowledge about Kerberos and want simply automate API calls to a REST endpoints secured by SPNEGO.
Here is what you need to do:
curl
7.38.0 against MIT Kerberoscurl --version
mentioning GSS-API and SPNEGO and with ldd
linked against your MIT Kerberos version.ktutil
or mskutil
kinit -k -t <path-to-keytab> <principal-from-keytab>
klist
that you have a ticket cacheEnvironment is now ready to go:
KRB5CCNAME=<some-non-default-path>
KRB5_CLIENT_KTNAME=<path-to-keytab>
curl --negotiate -u : <URL>
MIT Kerberos will detect that both environment variables are set, inspect them, automatically obtain a TGT with your keytab, request a service ticket and pass to curl
. You are done.
Note: this will not work with Heimdal.