hyperledger:Error: code = Unavailable desc = grpc: the connection is unavailable Usage: peer channel create [flags] - hyperledger-fabric

Question

root#bq4_node1:/opt/fabric/bin# $FABRIC_ROOT/bin/peer channel create -o orderer.local:7050 -f $FABRIC_CFG_PATH/channel-artifacts/channel.tx -c mychannel -t 30 --tls true --cafile $ordererCa
Error: Error connecting due to rpc error: code = Unavailable desc = grpc: the connection is unavailable
Usage:
peer channel create [flags]

Answer 1

Although, not very clear what exactly you are trying to do, I would guess it's somehow related to the channel creation and joining a new peer to that channel.
First of all please take a look on Hyperledger Fabric documentation and tutorial on Writing Your First Application. There is also "Building Your First Network", also make sure you have followed Prerequisites.
You need to start with creating crypto material for your network entities: peer and ordering service, you can leverage cryptogen tool to receive root CA keys and signed certificates for peers and users. Here is the example of crypto-config.yaml, which will allow to generate orderer organization related crypto material as well as for two peers organizations:
# ---------------------------------------------------------------------------
# "OrdererOrgs" - Definition of organizations managing orderer nodes
# ---------------------------------------------------------------------------
OrdererOrgs:
Specs:
- Hostname: orderer
# ---------------------------------------------------------------------------
# "PeerOrgs" - Definition of organizations managing peer nodes
# ---------------------------------------------------------------------------
PeerOrgs:
- Name: Org1
Domain: org1.example.com
Template:
Count: 2
Users:
Count: 1
# ---------------------------------------------------------------------------
# Org2: See "Org1" for full specification
# ---------------------------------------------------------------------------
- Name: Org2
Domain: org2.example.com
Template:
Count: 2
Users:
Count: 1
You can use cryptogen to generate results:
cryptogen generate --config=crypto-config.yaml --output=.
Next, you can use configtxgen to create configuration transaction which will allow to produce genesis block and create the channel, here an additional example. Command line command:
Generate genesis block for ordering service:
FABRIC_CFG_PATH=. configtxgen -profile TwoOrgsOrdererGenesis -outputBlock genesis.block
Generate config transaction to create new channel:
FABRIC_CFG_PATH=. configtxgen -profile TwoOrgsChannel -channelID mychannel -outputCreateChannelTx=mychannel.tx
Finally you can use peer cli command to create a new channel as you have tried in your question:
peer channel create -o orderer.local:7050 -f mychannel.tx -c mychannel -t 30 --tls true --cafile $ordererCa
Also please make sure that orderer.local is the host name of the available ordering service and also environmental variables for endorsing peers correctly configured and peer is running.