Coming from .NET dev/architect background means that there is a lot to learn in terms of networking and Linux management. Here are CKA curriculum requirements for networking:
CKA exam related commands:
Description: display and change the state of network interfaces.
Use cases:
- identify networking interface for cluster connectivity (ens3)
- show MAC address on the ens3 network interface (ip link show dev ens3)
Description: display IP Addresses and property information assigned to network interfaces.
Use cases:
- check network range of cluster nodes
Description: view routing table on the host.
Use cases:
- check default route for dns resolution (ip route show default)
Description: Using the arp command allows you to display and modify the Address Resolution Protocol (ARP) cache. An ARP cache is a simple mapping of IP addresses to MAC addresses. Each time a computer’s TCP/IP stack uses ARP to determine the Media Access Control (MAC) address for an IP address, it records the mapping in the ARP cache so that future ARP lookups go faster.
Use cases:
- check MAC address of a node
Description: query DNS server to resolve domain name
Use cases: check if k9s DNS server (like Core DNS) is working correctly
Description: query DNS server to resolve domain name, similar to nslookup but returns more details
Use cases: check if k9s DNS server (like Core DNS) is working correctly
Use cases:
- find paths to certificates and other settings for CNI etc
ps -aux | grep kubelet
Description: In computing, netstat (network statistics) is a command-line tool that displays network connections (both incoming and outgoing), routing tables, and a number of network interface (network interface controller or software-defined network interface) and network protocol statistics
Use cases:
- check
Description: - check what opened a socket
https://github.com/containernetworking/cni
cat /etc/cni/net.d/10-weave.conf - check CNI settings (in this case weave), plugin configuration, etc