I have private net and created 2 accounts using geth...I connected private net to metamask but accounts were not visible...I didn't get any seed while creating accounts using geth...Is the only option is to import account in metamask?
you can't get it.
You didn't get any seed because the accounts created with
geth aren't part of a Herarchical Deterministic Wallet.
The seed is a 12-word composition called mnemonic, which is derivated via HMA-SHA512, in order to obtein all the accounts of a (HDW).
By creating accounts with geth you'll never be able to get a seed, because the accounts don't come from it.
Anyways, you can import your account into Metamask as said on this post response:
You can now import single/"loose"(as we call) keys into MetaMask if you click the menu in the top right corner. It will drop down with the option "Import account", you can click that and it will take you to a view where it will ask you to import your private key or json file.
Hope it helps.