Verified in 6.6.0:

[arunkumar@node1-mad-hatter-testing-centos7 cb-non-package-installer]$ ./cb-non-package-installer --install --install-location ~/couchbase-home/ --package ~/couchbase-server-community-6.6.0-7899-centos7.x86_64.rpm
Successfully installed
[arunkumar@node1-mad-hatter-testing-centos7 cb-non-package-installer]$ cd ../couchbase-home/opt/couchbase/bin/
[arunkumar@node1-mad-hatter-testing-centos7 bin]$ ./couchbase-server --start

The maximum number of processes for the couchbase user is set too low (4096).
It must be at least 10000.

Normally this can be increased by adding the following lines to
/etc/security/limits.conf:

couchbase soft nproc <value>
couchbase hard nproc <value>

Where <value> is greater than 10000. The procedure may be totally
different if you're running so called "non-root/non-sudo install" or
if you've built Couchbase Server from source.

The maximum number of open files for the couchbase user is set too low (1024).
It must be at least 70000.

Normally this can be increased by adding the following lines to
/etc/security/limits.conf:

couchbase soft nofile <value>
couchbase hard nofile <value>

Where <value> is greater than 70000. The procedure may be totally
different if you're running so called "non-root/non-sudo install" or
if you've built Couchbase Server from source.

Build python_tools::cb-non-package-installer-6.6.0-8 contains cb-non-package-installer commit 3734f4d with commit message:
MB-40675 Fix for community edition non root install

Works with this fix: http://review.couchbase.org/c/cb-non-package-installer/+/133415

[arunkumar@node1-mad-hatter-testing-centos7 cb-non-package-installer]$ ./cb-non-package-installer --install --install-location ~/couchbase-home/ --package ~/couchbase-server-community-6.6.0-7899-centos7.x86_64.rpm
Successfully installed