Dgraph-alpha fails on ubuntu (Installscript with system.d)

i use the command curl https://get.dgraph.io -sSf | bash that without -s -- --systemd, and i successfully install the dgraph , i type the command dgraph version , and i got

root@iZuf68nltmjhh98k0z2rohZ:~# dgraph version

Dgraph version   : v21.12.0
Dgraph codename  : zion
Dgraph SHA-256   : 078c75df9fa1057447c8c8afc10ea57cb0a29dfb22f9e61d8c334882b4b4eb37
Commit SHA-1     : d62ed5f15
Commit timestamp : 2021-12-02 21:20:09 +0530
Branch           : HEAD
Go version       : go1.17.3
jemalloc enabled : true

For Dgraph official documentation, visit https://dgraph.io/docs.
For discussions about Dgraph     , visit http://discuss.hypermode.com.
For fully-managed Dgraph Cloud   , visit https://dgraph.io/cloud.

Licensed variously under the Apache Public License 2.0 and Dgraph Community License.
Copyright 2015-2021 Dgraph Labs, Inc.

but when i type the command dgraph alpha, i got many code showing in the console and some error like this below :

g":n=t.etag;break;case"weak":n=t.wetag;break;default:throw new TypeError("unknown value for etag function: "+e)}return n},t.compileQueryParser=function(e){var t;if("function"==typeof e)return e;switch(e){case!0:t=d.parse;break;case!1:t=h;break;case"extended":t=f;break;case"simple":t=d.parse;break;default:throw new TypeError("unknown value for query parser function: "+e)}return t},t.compileTrust=function(e){return"function"==typeof e?e:!0===e?function(){return!0}:"number"==typeof e?function(t,n){return n<e}:("string"==typeof e&&(e=e.split(/ *, */)),l.compile(e||[]))},t.setCharset=function(e,t){if(!e||!t)return e;var n=r.parse(e);return n.parameters.charset=t,r.format(n)}},8706:(e,t,n)=>{"use strict";var i=n(5158)("express:view"),a=n(5622),r=n(5747),o=a.dirname,s=a.basename,c=a.extname,p=a.join,l=a.resolve;function u(e,t){var a=t||{};if(this.defaultEngine=a.defaultEngE0519 11:09:13.661355 2910132 run.go:543] Lambda server at port: 20000 stopped with error: exit status 1
E0519 11:09:14.291252 2910132 groups.go:1223] Error during SubscribeForUpdates for prefix "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x15dgraph.graphql.schema\x00": Unable to find any servers for group: 1. closer err: <nil>
E0519 11:09:14.587462 2910132 pool.go:311] CONN: Unable to connect with localhost:5080 : rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp [::1]:5080: connect: connection refused"
E0519 11:09:15.143381 2910132 admin.go:1137] namespace: 0. Error reading GraphQL schema: Please retry again, server is not ready to accept requests.
E0519 11:09:15.292252 2910132 groups.go:1223] Error during SubscribeForUpdates for prefix "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x15dgraph.graphql.schema\x00": Unable to find any servers for group: 1. closer err: <nil>
^CI0519 11:09:15.585572 2910132 run.go:954] Caught Ctrl-C. Terminating now (this may take a few seconds)...
I0519 11:09:15.585614 2910132 run.go:959] Stopped before initialization completed

how can i slove the problem , thank you for any help !