Chapter 11. Network Observability CLI

Procedure

1. Download the oc netobserv CLI tar file.

2. Unpack the archive:

   $ tar xvf netobserv-cli.tar.gz

3. Make the file executable:

   $ chmod +x ./build/oc-netobserv

4. Move the extracted netobserv-cli binary to a directory that is on your PATH, such as /usr/local/bin/:

   $ sudo mv ./build/oc-netobserv /usr/local/bin/

Procedure

1. Capture flows with filters enabled by running the following command:

   $ oc netobserv flows --enable_filter=true --action=Accept --cidr=0.0.0.0/0 --protocol=TCP --port=49051

2. Add filters to the live table filter prompt in the terminal to further refine the incoming flows. For example:

   live table filter: [SrcK8S_Zone:us-west-1b] press enter to match multiple regular expressions at once

3. To stop capturing, press Ctrl+C. The data that was captured is written to two separate files in an ./output directory located in the same path used to install the CLI.

4. View the captured data in the ./output/flow/<capture_date_time>.json JSON file, which contains JSON arrays of the captured data.

   Example JSON file

   {
     "AgentIP": "10.0.1.76",
     "Bytes": 561,
     "DnsErrno": 0,
     "Dscp": 20,
     "DstAddr": "f904:ece9:ba63:6ac7:8018:1e5:7130:0",
     "DstMac": "0A:58:0A:80:00:37",
     "DstPort": 9999,
     "Duplicate": false,
     "Etype": 2048,
     "Flags": 16,
     "FlowDirection": 0,
     "IfDirection": 0,
     "Interface": "ens5",
     "K8S_FlowLayer": "infra",
     "Packets": 1,
     "Proto": 6,
     "SrcAddr": "3e06:6c10:6440:2:a80:37:b756:270f",
     "SrcMac": "0A:58:0A:80:00:01",
     "SrcPort": 46934,
     "TimeFlowEndMs": 1709741962111,
     "TimeFlowRttNs": 121000,
     "TimeFlowStartMs": 1709741962111,
     "TimeReceived": 1709741964
   }

5. You can use SQLite to inspect the ./output/flow/<capture_date_time>.db database file. For example:

   1. Open the file by running the following command:

      $ sqlite3 ./output/flow/<capture_date_time>.db

   2. Query the data by running a SQLite SELECT statement, for example:

      sqlite> SELECT DnsLatencyMs, DnsFlagsResponseCode, DnsId, DstAddr, DstPort, Interface, Proto, SrcAddr, SrcPort, Bytes, Packets FROM flow WHERE DnsLatencyMs >10 LIMIT 10;

      Example output

      12|NoError|58747|10.128.0.63|57856||17|172.30.0.10|53|284|1
      11|NoError|20486|10.128.0.52|56575||17|169.254.169.254|53|225|1
      11|NoError|59544|10.128.0.103|51089||17|172.30.0.10|53|307|1
      13|NoError|32519|10.128.0.52|55241||17|169.254.169.254|53|254|1
      12|NoError|32519|10.0.0.3|55241||17|169.254.169.254|53|254|1
      15|NoError|57673|10.128.0.19|59051||17|172.30.0.10|53|313|1
      13|NoError|35652|10.0.0.3|46532||17|169.254.169.254|53|183|1
      32|NoError|37326|10.0.0.3|52718||17|169.254.169.254|53|169|1
      14|NoError|14530|10.0.0.3|58203||17|169.254.169.254|53|246|1
      15|NoError|40548|10.0.0.3|45933||17|169.254.169.254|53|174|1

Procedure

1. Run the packet capture with filters enabled:

   $ oc netobserv packets --filter=tcp,80

2. Add filters to the live table filter prompt in the terminal to refine the incoming packets. An example filter is as follows:

   live table filter: [SrcK8S_Zone:us-west-1b] press enter to match multiple regular expressions at once

3. To stop capturing, press Ctrl+C.

4. View the captured data, which is written to a single file in an ./output/pcap directory located in the same path that was used to install the CLI:

   1. The ./output/pcap/<capture_date_time>.pcap file can be opened with Wireshark.