Skip to main content

Install Proxy Nodes


You can download the latest version of the kpn on Download page.

Installation ​

Linux Archive Distribution ​

The archive file consists of the executable binary and the configuration file structured as follows.

Note: Do NOT alter the file structure or file name. If you change it, the node may not function correctly.

- bin
|- kpn
|- kpnd
- conf
|- kpnd.conf

File NameFile Description
bin/kpnPN executable file
bin/kpndPN start/termination script file
conf/kpnd.confPN configuration file

The installation is the uncompression of the downloaded package where you want to install the package.

$ tar zxf kpn-vX.X.X-linux-amd64.tar.gz


$ tar zxf kpn-baobab-vX.X.X-linux-amd64.tar.gz

Note: it is recommended that the uncompressed directory kpn-linux-amd64/bin path should be added to the environment variable $PATH to run the kpn and kpnd globally. As an example,

$ export PATH=$PATH:~/downloaded/path/kpn-linux-amd64/bin

The other sections assume that the path is added to the variable.

RPM Distribution (RHEL/CentOS/Fedora) ​

You can install the downloaded RPM file with the following yum command.

$ yum install kpnd-vX.X.X.el7.x86_64.rpm


$ yum install kpnd-baobab-vX.X.X.el7.x86_64.rpm

Install from Klaytn Yum Repo ​

Alternatively, you can install kpnd from the Klaytn Yum repo, run:

$ sudo curl -o /etc/yum.repos.d/klaytn.repo && sudo yum install kpnd

Installed Location ​

The installed files are located as follows.

File NameLocation

Configuration ​

The PN configuration is to create a data directory and set up several values in the configuration file kpnd.conf.

  1. Create a PN Data Directory
  2. Install node key
  3. Install static-node.json
  4. Configure the PN with kpnd.conf.

PN Data Directory Creation ​

Considering the fact that the size of Klaytn blockchain data is always increased, it is recommended to use a big enough storage. You may need to create the directory on your desired path.

$ mkdir -p /var/kpnd/data

Install Node Key ​

In order to operate a PN, a nodekey is required. The KPN binary will create a new one for you if you do not have it. If you have one, you need to put your nodekey into the PN data directory. The way to create a nodekey is in the "Before You Install" section. The following command line copies the nodekey into the PN data directory.

$ cp nodekey /var/kpnd/data

Install static-nodes.json ​

The static-nodes.json should be created from the PN operator. It contains the addresses that your PN is connected to. It is recommended to add the addresses including your CN and a PN from another Core Cell. Please contact to the Klaytn official email for more details ( for Cypress or for Baobab).



The node URI of the PN is in the "Before You Install" section. (Note: This IP address is different from CN public IP.) The following command line copies the static-nodes.json file into the PN data directory.

$ cp static-nodes.json /var/kpnd/data

Update the Configuration File ​

Configuration File Location:

  • For the archive distribution, the config directory location defaults to $INSTALL_PATH/kpn-linux-amd64/conf/.
  • For the package distribution, the config directory defaults to /etc/kpnd/conf/.

Add Data Directory ​

You should update the the data directory environment variable $DATA_DIR on the configuration file kpnd.conf.


Fast Sync (Optional) ​

Each PN maintains a copy of the network's chain data. If a node is out of sync, it can obtain this data from other nodes in the network -- a process known as syncing. When a new PN is first started, it must download the entire chain data from the network.

To accelerate this process, you may perform a fast sync by downloading a snapshot of the chain data before starting the PN. This can dramatically reduce the time the PN will spend syncing on first start.

Download the latest chaindata snapshot from the Cypress snapshot archive or Baobab snapshot archive. Before starting kpnd, extract the snapshot inside the DATA_DIR you configured in kpnd.conf.

For example:

$ tar -C /var/kpnd/data -xvf klaytn-cypress-chaindata-latest.tar.gz


$ tar -C /var/kpnd/data -xvf klaytn-baobab-chaindata-latest.tar.gz

After the data is extracted, you may start the PN normally.

You can refer to detailed information in the Chaindata change

Startup the PN ​

PN Start/Stop ​

You can start/stop the Klaytn service with the following systemctl command.

Note: This requires root privileges.


$ systemctl start kpnd.service


$ systemctl stop kpnd.service


$ systemctl status kpnd.service

Troubleshooting ​

If you meet the following error,

Failed to start kpnd.service: Unit not found.

reload the systemd manager configuration with the following command.

$ systemctl daemon-reload

Testing the Core Cell ​

It is time to check that Core Cell is successfully installed and it is working as expected after installation.

Process Status ​

It is possible to check the status of PN's process using the status commands systemctl and kpnd.

systemctl ​

systemctl is installed along with the RPM and the status of PN can be checked as follows.

$ systemctl status kpnd.service
● kpnd.service - (null)
Loaded: loaded (/etc/rc.d/init.d/kpnd; bad; vendor preset: disabled)
Active: active (running) since Wed 2019-01-09 11:42:39 UTC; 1 months 4 days ago
Docs: man:systemd-sysv-generator(8)
Process: 29636 ExecStart=/etc/rc.d/init.d/kpnd start (code=exited, status=0/SUCCESS)
Main PID: 29641 (kpn)
CGroup: /system.slice/kpnd.service
└─29641 /usr/local/bin/kpn --networkid 1000 --datadir /kpnd_home --port 32323 --srvtype fasthttp --metrics --prometheus --verbosity 3
Jan 09 11:42:39 ip-10-11-2-101.ap-northeast-2.compute.internal systemd[1]: Starting (null)...
Jan 09 11:42:39 ip-10-11-2-101.ap-northeast-2.compute.internal kpnd[29636]: Starting kpnd: [ OK ]
Jan 09 11:42:39 ip-10-11-2-101.ap-northeast-2.compute.internal systemd[1]: Started (null).

You can check the current status such as Active: active (running) in the above example.

kpnd ​

kpnd is installed along with the package and the status of PN can be checked as follows.

$ kpnd status
kpnd is running

Logs ​

The log is stored in kpnd.out file located in the path defined in the LOG_DIR field of the kpnd.conf file. When the node works properly, you can see that each block is created per second as follows.


$ tail kpnd.out
INFO[02/13,07:02:24 Z] [35] Commit new mining work number=11572924 txs=0 elapsed=488.336Β΅s
INFO[02/13,07:02:25 Z] [5] Imported new chain segment blocks=1 txs=0 mgas=0.000 elapsed=1.800ms mgasps=0.000 number=11572924 hash=f46d09…ffb2dc cache=1.59mB
INFO[02/13,07:02:25 Z] [35] Commit new mining work number=11572925 txs=0 elapsed=460.485Β΅s
INFO[02/13,07:02:25 Z] [35] πŸ”— block reached canonical chain number=11572919 hash=01e889…524f02
INFO[02/13,07:02:26 Z] [14] Committed address=0x1d4E05BB72677cB8fa576149c945b57d13F855e4 hash=1fabd3…af66fe number=11572925
INFO[02/13,07:02:26 Z] [5] Imported new chain segment blocks=1 txs=0 mgas=0.000 elapsed=1.777ms mgasps=0.000 number=11572925 hash=1fabd3…af66fe cache=1.59mB
INFO[02/13,07:02:26 Z] [35] Commit new mining work number=11572926 txs=0 elapsed=458.665Β΅s
INFO[02/13,07:02:27 Z] [14] Committed address=0x1d4E05BB72677cB8fa576149c945b57d13F855e4 hash=60b9aa…94f648 number=11572926
INFO[02/13,07:02:27 Z] [5] Imported new chain segment blocks=1 txs=0 mgas=0.000 elapsed=1.783ms mgasps=0.000 number=11572926 hash=60b9aa…94f648 cache=1.59mB
INFO[02/13,07:02:27 Z] [35] Commit new mining work number=11572927 txs=0 elapsed=483.436Β΅s

kpn console ​

Klaytn provides a CLI client: kpn console. However, a PN may disable the RPC interface for the client due to the security reason. Another way of using the client is to connect to the process via IPC (inter-process communication).

The IPC file klay.ipc is located in the data directory on a PN.

Please execute the following command and check out the result.

$ kpn attach /var/kpnd/data/klay.ipc
Welcome to the Klaytn JavaScript console!
instance: Klaytn/vX.X.X/XXXX-XXXX/goX.X.X
coinbase: 0x67f68fdd9740fd7a1ac366294f05a3fd8df0ed40
at block: 11573551 (Wed, 13 Feb 2019 07:12:52 UTC)
datadir: /var/kpnd/data
modules: admin:1.0 debug:1.0 istanbul:1.0 klay:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0

You can check the usable commands on API Document

The useful APIs to check the status of a PN:

  • klay.blockNumber (to get the latest block number)
  • net.peerCount (to get the number of the connected Klaytn nodes currently)

klay.blockNumber ​

You can get the latest block number to see if blocks are created (for CNs) or propagated (for CNs and PNs) properly based on your node type.

> klay.blockNumber

net.peerCount ​

> net.peerCount

The above command line returns a different value based on the node type.

  • CN: the number of connected CNs + the number of connected PNs.
  • PN: the number of connected CNs + the number of connected PNs + the number of connected ENs.
Make this page better