The following error occurred when trying to start the container with docker-compose up, so the remedy is described.
Starting lb ... error
ERROR: for lb Cannot start service lb: Ports are not available: listen tcp 0.0.0.0:80: bind: address already in use
Literally, it cannot be used because another application is using port 80. So look for the process that is using the port.
$ sudo lsof -i -P | grep ":80"
It turns out that httpd is using port 80.
httpd 103 root 4u IPv6 0xb54e8c868de16e45 0t0 TCP *:80 (LISTEN)
httpd 1221 _www 4u IPv6 0xb54e8c868de16e45 0t0 TCP *:80 (LISTEN)
com.docke 2202 ishiharanaohiro 83u IPv6 0xb54e8c868494ae45 0t0 TCP *:8025 (LISTEN)
Delete the PID (103, 1221) for httpd.
$ kill -l 103
$ kill -l 1221
Start safely with docker-compose up -d
. Congratulations!
Starting lb ... done