Query regarding Xtrabackup issue

I am doing POC on Kubernetes. I am Following below links for setup master/slave setup using MySQL & xtrabackup.
Running below issue: In our env. we have multiple DC and in. order to communicate one DC to another we have to use kube load balancer service. I plan is to setup one master on one DC and slave on another DC and they will communicate via load balancer.  I have tested the setup but getting below error.


➜  working k logs -f -c xtrabackup mysql-master-5b67c98658-z4vck

+ cd /var/lib/mysql

+ exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c 'xtrabackup --backup --slave-info --stream=xbstream --host= --user=root --password=root'

200407 19:16:32  version_check Connecting to MySQL server with DSN 'dbi:mysql:;mysql_read_default_group=xtrabackup;host=;port=3306;mysql_socket=/var/run/mysqld/mysqld.sock' as 'root'  (using password: YES).

200407 19:16:32  version_check Connected to MySQL server

200407 19:16:32  version_check Executing a version check against the server...

200407 19:16:32  version_check Done.

200407 19:16:32 Connecting to MySQL server host:, user: root, password: set, port: 3306, socket: /var/run/mysqld/mysqld.sock

Using server version 5.7.29-log

xtrabackup version 2.4.4 based on MySQL server 5.7.13 Linux (x86_64) (revision id: df58cf2)

xtrabackup: uses posix_fadvise().

xtrabackup: cd to /var/lib/mysql

xtrabackup: open files limit requested 0, set to 1048576

xtrabackup: using the following InnoDB configuration:

xtrabackup:   innodb_data_home_dir = .

xtrabackup:   innodb_data_file_path = ibdata1:12M:autoextend

xtrabackup:   innodb_log_group_home_dir = ./

xtrabackup:   innodb_log_files_in_group = 2

xtrabackup:   innodb_log_file_size = 50331648

InnoDB: Number of pools: 1

200407 19:16:32 >> log scanned up to (12480867)

xtrabackup: Generating a list of tablespaces

InnoDB: Allocated tablespace ID 2 for mysql/plugin, old maximum was 0

200407 19:16:32 [01] Streaming ./ibdata1

xtrabackup: Error writing file 'UNOPENED' (Errcode: 32 - Broken pipe)

xb_stream_write_data() failed.

xtrabackup: Error writing file 'UNOPENED' (Errcode: 32 - Broken pipe)

[01] xtrabackup: Error: xtrabackup_copy_datafile() failed.

[01] xtrabackup: Error: failed to copy datafile.

Ncat: assertion failed: count <= INT_MAX QUITTING.

It's working fine 

I have the same issue when building MySQL cluster and that happens if I try to check if xtrabackup is ready 
while ! nc -z xtrabackup-host 3307; do  sleep 5; done
if I comment out this line before I start to restore database I don’t get error INT_MAX QUITTING any more 
maybe this till help