ethereum geth rpc port problem

[myapple]

thanks
I am setting up private chain and use web3 to connect it
I found the port 8545 always not open
Here I use Geth and vps Ubuntu
I try to run Geth with —rpcaddr ‘0.0.0.0’ and —rpcport 8545
I tried netstat and I found 8545 not open
Even Ipc file not exist

How to run a geth test to let 8545 open?
Thanks