calamari server starts, but the GUI doesn't show up

I could start the calamari server successfully, accessing the calamari GUI , it shows that the server is not available.
[root@centos7os calamari-clients-1.2.2]# calamari-ctl initialize
[INFO] Loading configuration..
[INFO] Starting/enabling salt...
[INFO] Starting/enabling postgres...
[INFO] Updating database...
[INFO] Initializing web interface...
[INFO] Starting/enabling services...
[INFO] Restarting services...
[INFO] Complete.
[root@centos7os calamari-clients-1.2.2]#
[root@centos7os tmp]# ps -eaf | grep calamari*
root 17001 19099 0 15:28 ? 00:00:03 /opt/calamari/venv/bin/python /opt/calamari/venv/bin/cthulhu-manager
postgres 17014 15255 0 15:28 ? 00:00:00 postgres: calamari calamari ::1(34259) idle
postgres 17021 15255 0 15:28 ? 00:00:00 postgres: calamari calamari ::1(34262) idle
root 18403 17256 0 16:04 pts/0 00:00:00 grep --color=auto calamari*
root 19242 19099 0 14:12 ? 00:00:01 /opt/calamari/venv/bin/python /opt/calamari/venv/bin/carbon-cache.py --debug --config /etc/graphite/carbon.conf start
apache 20425 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20426 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20427 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20428 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20429 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20430 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20431 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
apache 20432 20422 0 14:12 ? 00:00:00 calamari-httpd -DFOREGROUND
[root@centos7os tmp]#

Any suggestion to debug the issue, the guest OS is Centos 7 and build the server code following the instruction in this link:

http://karan-mj.blogspot.com/2014/09/ceph-calamari-survival-guide.html

Build the client code following the instruction:

Note: These instructions are deliberately non-system specific. Please visit the wiki and help us write better more distro and release specific instructions.
• install nodejs, a recent version like 0.10.
• install npm, a recent version (1.4 cause troubles building package, use sudo npm install -g npm@next)
• install grunt-cli globally via npm
• Ruby gem and compass via gem
• make sure your system has a recent gnu compatible make binary
• checkout the code git clone git@github.com:ceph/calamari-clients.git
• cd into calamari-clients
• to build: make dist
This will build all the modules.

In the deployment, copy all the items under the subdir (after gunzip and tar -xvf) to /opt/calamari/webapp/content

drwxr-xr-x. 4 root root 4096 Jul 23 16:59 admin
-rw-r--r--. 1 root root 1398 Jul 23 16:59 bootstrap.md
-rw-r--r--. 1 root root 2222 Jul 23 16:59 calamari-clients.suse.spec
-rw-r--r--. 1 root root 1170 Jul 23 16:59 clients.spec
-rw-r--r--. 1 root root 1646 Jul 23 16:59 COPYING
drwxr-xr-x. 5 root root 4096 Jul 23 16:59 dashboard
-rwxr-xr-x. 1 root root 874 Jul 23 16:59 get-versions.sh
-rw-r--r--. 1 root root 1127 Jul 23 16:59 LICENSE.txt
drwxr-xr-x. 4 root root 4096 Jul 23 16:59 login
-rw-r--r--. 1 root root 4569 Jul 23 16:59 Makefile
-rw-r--r--. 1 root root 910 Jul 23 16:59 Makefile.sub
drwxr-xr-x. 5 root root 4096 Jul 23 16:59 manage
-rw-r--r--. 1 root root 856 Jul 23 16:59 README.md
drwxr-xr-x. 2 root root 4096 Jul 23 16:59 screenshots
-rw-r--r--. 1 root root 815 Jul 23 16:59 ui.build.instructions.md
drwxr-xr-x. 3 root root 4096 Jul 23 16:59 utils
drwxr-xr-x. 9 root root 4096 Jul 23 16:59 vagrant
[root@centos7os calamari-clients-1.2.2]#


Start with the reported calamari-ctl initialize output and the deployed content under /opt/calamari/webapp/content. Read ui.build.instructions.md and the Makefile in calamari-clients, then verify whether the built client assets are served and whether the GUI can reach the running server; done means the GUI reports the server as available.

Written by the indexing model from the issue text.