The symlinks in your rc*.d directories show an interesting pattern - all runlevels (0-6) have K15httpd (Kill) scripts, but no S* (Start) scripts. This explains why Apache won't autostart. On Amazon Linux AMI (which uses SysVinit), services need S* symlinks in the appropriate runlevel directories to start automatically.

# Current incorrect state
find /etc/rc.d -name "*httpd*" | xargs ls -l

# Expected correct state should include S* symlinks
S85httpd -> ../init.d/httpd  # In runlevels where it should start (typically 3,5)

For Amazon Linux AMI (based on RHEL/CentOS 6), you should use the chkconfig command instead of manually managing symlinks:

# Check current configuration
chkconfig --list httpd

# Correct configuration (example output):
httpd           0:off   1:off   2:on    3:on    4:on    5:on    6:off

# To set this up:
sudo chkconfig httpd on

If you're using a newer Amazon Linux AMI version with systemd, the approach changes:

# Check if systemd is present
which systemctl

# Enable autostart
sudo systemctl enable httpd.service
sudo systemctl is-enabled httpd.service  # Verify

Sometimes autostart fails due to missing dependencies. Check the init script headers:

# View init script requirements
head -n 20 /etc/rc.d/init.d/httpd

# Look for these lines:
# chkconfig: 345 85 15
# description: Apache web server

The numbers after "chkconfig:" indicate:
- Runlevels (3,4,5)
- Start priority (85)
- Kill priority (15)

If chkconfig isn't working, you can manually create symlinks:

# For runlevel 3 (multi-user)
ln -s /etc/rc.d/init.d/httpd /etc/rc.d/rc3.d/S85httpd

# For runlevel 5 (graphical)
ln -s /etc/rc.d/init.d/httpd /etc/rc.d/rc5.d/S85httpd

After making changes, test without rebooting:

# Simulate startup sequence
sudo /etc/rc.d/rc.local
sudo service httpd status

# Or force runlevel change
sudo telinit 3

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When dealing with Amazon Linux AMI 2012.03, I noticed Apache HTTPD (httpd) fails to start automatically on system boot despite manual starts working perfectly via:

/etc/init.d/httpd start

The symlinks in /etc/rc.d/ appear correctly configured:

find /etc/rc.d -name "*httpd*" | xargs ls -l
-rwxr-xr-x 1 root root 3371 Feb 16  2012 /etc/rc.d/init.d/httpd
lrwxrwxrwx 1 root root   15 Apr 14  2012 /etc/rc.d/rc0.d/K15httpd -> ../init.d/httpd
[... other symlinks ...]

The key issue lies in the symlink naming convention. Notice all links begin with K15 (kill) rather than S85 (start) in runlevels 2-5. This explains why other services like MongoDB and Postfix start while Apache doesn't.

To verify runlevel configuration:

chkconfig --list httpd
httpd           0:off   1:off   2:off   3:off   4:off   5:off   6:off

For SysV init systems, use chkconfig to properly configure startup:

chkconfig --add httpd
chkconfig httpd on

This creates correct symlinks for all runlevels. Verify with:

ls -l /etc/rc.d/rc{3,4,5}.d/S*httpd*

For systems transitioning to systemd (though not applicable to 2012.03 AMI):

systemctl enable httpd
systemctl is-enabled httpd

If permissions are suspected:

ls -l /etc/init.d/httpd
chmod +x /etc/init.d/httpd

Add debug output to the init script:

vim /etc/init.d/httpd
# Add near the top:
echo "Apache init script executed at $(date)" >> /var/log/httpd-init.log

Check boot logs post-reboot:

dmesg | grep httpd
journalctl -b | grep httpd  # For newer systems

After making changes, validate with:

chkconfig --list httpd
# Should show 'on' for runlevels 2-5

reboot
ps aux | grep httpd
curl -I localhost