Boot Time State Management

Question 1

What is the purpose of boot-time state management?

Answer 1

Controls when services start during Linux boot; systemd provides commands to enable, disable, mask, and unmask services.

Question 2

What does systemctl enable do?

Answer 2

Configures a service to start automatically at boot; creates a symbolic link between the service unit file and a target (e.g., multi-user.target).

Question 3

What is the syntax for enabling a service?

Answer 3

sudo systemctl enable <service-name></service-name>

Question 4

Give an example of enabling Apache service.

Answer 4

sudo systemctl enable apache2.service

Question 5

What output is shown when enabling a service?

Answer 5

Created symlink /etc/systemd/system/multi-user.target.wants/apache2.service → /lib/systemd/system/apache2.service; links Apache to multi-user.target so it starts automatically at boot.

Question 6

What does systemctl disable do?

Answer 6

Prevents a service from starting automatically at boot; removes the symbolic link created by enable; does not stop a running service or block manual starts.

Question 7

What is the syntax for disabling a service?

Answer 7

sudo systemctl disable <service-name></service-name>

Question 8

Give an example of disabling Apache service.

Answer 8

sudo systemctl disable apache2.service

Question 9

What output is shown when disabling a service?

Answer 9

Removed /etc/systemd/system/multi-user.target.wants/apache2.service; Apache will not start at boot but can be started manually with sudo systemctl start apache2.service.

Question 10

What does systemctl mask do?

Answer 10

Blocks a service from being started manually or automatically; replaces the service unit file with a symlink to /dev/null.

Question 11

What is the syntax for masking a service?

Answer 11

sudo systemctl mask <service-name></service-name>

Question 12

Give an example of masking Apache service.

Answer 12

sudo systemctl mask apache2.service

Question 13

What output is shown when masking a service?

Answer 13

Created symlink /etc/systemd/system/apache2.service → /dev/null; any attempt to start Apache will fail.

Question 14

What does systemctl unmask do?

Answer 14

Removes the mask from a service; deletes the symlink to /dev/null; allows the service to be enabled or started again.

Question 15

What is the syntax for unmasking a service?

Answer 15

sudo systemctl unmask <service-name></service-name>

Question 16

Give an example of unmasking Apache service.

Answer 16

sudo systemctl unmask apache2.service; no output unless an error occurs.