collectd writing

collectd is a daemon used to collect system performance metric data. collectd provides various storage mechanisms to store different values. It periodically counts system performance statistics while the system is running and storing information. You can use this information to help identify current system performance bottlenecks and predict future system load.

You can write the data collected by collectd to TDengine by simply modifying the configuration of collectd to the domain name (or IP address) and corresponding port of the server running taosAdapter. It can take full advantage of TDengine's efficient storage query performance and clustering capability for time-series data.

Prerequisites

Writing collectd data to the TDengine requires several preparations.

• The TDengine cluster is deployed and running properly
• taosAdapter is installed and running, please refer to taosAdapter's manual for details
• collectd has been installed. Please refer to the official documentation to install collectd

Configuration steps

Configuring taosAdapter

To configure taosAdapter to receive collectd data.

• Enable the configuration item in the taosAdapter configuration file (default location is /etc/taos/taosadapter.toml)

...
[opentsdb_telnet]
enable = true
maxTCPConnections = 250
tcpKeepAlive = false
dbs = ["opentsdb_telnet", "collectd", "icinga2", "tcollector"]
ports = [6046, 6047, 6048, 6049]
user = "root"
password = "taosdata"
...

The default database name written by taosAdapter is collectd. You can also modify the taosAdapter configuration file dbs entry to specify a different name. user and password are the values configured by the actual TDengine. After changing the configuration file, you need to restart the taosAdapter.

• You can also enable the taosAdapter to receive collectd data by using the taosAdapter command-line parameters or by setting environment variables.

Configure collectd

#collectd collectd uses a plugin mechanism to write the collected monitoring data to different data storage software in various forms. tdengine supports both direct collection plugins and write_tsdb plugins.

Configure the direct collection plugin

Modify the relevant configuration items in the collectd configuration file (default location /etc/collectd/collectd.conf).

LoadPlugin network
<Plugin network>
         Server "<taosAdapter's host>" "<port for collectd direct>"
</Plugin>

where <taosAdapter's host> fills in the server's domain name or IP address running taosAdapter. <port for collectd direct> fills in the port that taosAdapter uses to receive collectd data (default is 6045).

An example is as follows.

LoadPlugin network
<Plugin network
         Server "127.0.0.1" "6045"
</Plugin>

Configure write_tsdb plugin data

Modify the relevant configuration items in the collectd configuration file (default location /etc/collectd/collectd.conf).

LoadPlugin write_tsdb
<Plugin write_tsdb>
        <Node>
                Host "<taosAdapter's host>"
                Port "<port for collectd write_tsdb plugin>"
                ...
        </Node>
</Plugin>

Where <taosAdapter's host> is the domain name or IP address of the server running taosAdapter. <port for collectd write_tsdb plugin> Fill in the data that taosAdapter uses to receive the collectd write_tsdb plugin (default is 6047).

LoadPlugin write_tsdb
<Plugin write_tsdb>
        <Node>
                Host "127.0.0.1"
                Port "6047"
                HostTags "status=production"
                StoreRates false
                AlwaysAppendDS false
        </Node
</Plugin>

Then restart collectd.

systemctl restart collectd

Verification method

Restart collectd

sudo systemctl restart collectd

Use the TDengine CLI to verify that collectd's data is written to TDengine and can read out correctly.

taos> show databases;
              name              |      created_time       |   ntables   |   vgroups   | replica | quorum |  days  |           keep           |  cache(MB)  |   blocks    |   minrows   |   maxrows   | wallevel |    fsync    | comp | cachelast | precision | update |   status   |
====================================================================================================================================================================================================================================================================================
 collectd                       | 2022-04-20 09:27:45.460 |          95 |           1 |       1 |      1 |     10 | 3650                     |          16 |           6 |         100 |        4096 |        1 |        3000 |    2 |         0 | ns        |      2 | ready      |
 log                            | 2022-04-20 07:19:50.260 |          11 |           1 |       1 |      1 |     10 | 3650                     |          16 |           6 |         100 |        4096 |        1 |        3000 |    2 |         0 | ms        |      0 | ready      |
Query OK, 2 row(s) in set (0.003266s)

taos> use collectd;
Database changed.

taos> show stables;
              name              |      created_time       | columns |  tags  |   tables    |
============================================================================================
 load_1                         | 2022-04-20 09:27:45.492 |       2 |      2 |           1 |
 memory_value                   | 2022-04-20 09:27:45.463 |       2 |      3 |           6 |
 df_value                       | 2022-04-20 09:27:45.463 |       2 |      4 |          25 |
 load_2                         | 2022-04-20 09:27:45.501 |       2 |      2 |           1 |
 load_0                         | 2022-04-20 09:27:45.485 |       2 |      2 |           1 |
 interface_1                    | 2022-04-20 09:27:45.488 |       2 |      3 |          12 |
 irq_value                      | 2022-04-20 09:27:45.476 |       2 |      3 |          31 |
 interface_0                    | 2022-04-20 09:27:45.480 |       2 |      3 |          12 |
 entropy_value                  | 2022-04-20 09:27:45.473 |       2 |      2 |           1 |
 swap_value                     | 2022-04-20 09:27:45.477 |       2 |      3 |           5 |
Query OK, 10 row(s) in set (0.002236s)

taos> select * from collectd.memory_value limit 10;
              ts               |           value           |              host              |         type_instance          |           type           |
=========================================================================================================================================================
 2022-04-20 09:27:45.459653462 |        54689792.000000000 | shuduo-1804                    | buffered                       | memory                   |
 2022-04-20 09:27:55.453168283 |        57212928.000000000 | shuduo-1804                    | buffered                       | memory                   |
 2022-04-20 09:28:05.453004291 |        57942016.000000000 | shuduo-1804                    | buffered                       | memory                   |
 2022-04-20 09:27:45.459653462 |      6381330432.000000000 | shuduo-1804                    | free                           | memory                   |
 2022-04-20 09:27:55.453168283 |      6357643264.000000000 | shuduo-1804                    | free                           | memory                   |
 2022-04-20 09:28:05.453004291 |      6349987840.000000000 | shuduo-1804                    | free                           | memory                   |
 2022-04-20 09:27:45.459653462 |       107040768.000000000 | shuduo-1804                    | slab_recl                      | memory                   |
 2022-04-20 09:27:55.453168283 |       107536384.000000000 | shuduo-1804                    | slab_recl                      | memory                   |
 2022-04-20 09:28:05.453004291 |       107634688.000000000 | shuduo-1804                    | slab_recl                      | memory                   |
 2022-04-20 09:27:45.459653462 |       309137408.000000000 | shuduo-1804                    | used                           | memory                   |
Query OK, 10 row(s) in set (0.010348s)