Telco and IT

Everything which is related to Telecommunications, IT and my work

OUI issue NGINST-64002: Error occurred in validation of: “Host Name”

When installing an Oracle application using OUI (Oracle Universal Installer) sometimes it verifies if a given host is reachable. 

Unfortunately, in my case, it was always failing:

All this despite the host was perfectly reachable using Ping:

So what was happening? The OUI is using under the hood Java’s InetAddress.isReachable(). The algorithm is:

  1.  Try to send ICMP “ping”, if that fails
  2.  Try to use ICMP Echo service
Unfortunately, check (1) can only be attempted if you run the app with an elevated permissions (root or sudo), which typically does not happen.
So it goes to (2) and makes the following attempt:

So it probes Echo service over TCP port 7. 


Here you are! It was a missing firewall rule. Just open TCP/7 port on the target (checked) system and the test is passing like a charm.

Details for nerds

A small tool to run the test. Just run it as shown below:

Compare with same test ran using sudo. This time the test is done using ICMP, so no TCP/7 port needed. But as mentioned earlier, this is highly impractical and even not recommended:

Prometheus Node Exporter /lib/init/init-d-script: /usr/bin/daemon: not found

After Ubuntu upgrade 18.04 -> 18.10, Prometheus Node Exporter started to complain:

Fix for this is quite easy – just install missing dependency:

After that daemon can be started:

Oracle Coherence – description of federation member states

States of Oracle Coherence federation are not very well described in the documentation. So I thought it would be good to ask at the source. Thanks for Patrick F for all these explanations!

Stopped states – Federation is not federating data to the destination, nor is it keeping a backlog of changes to send to the destination.  A “start” operation must be performed to start federating data again:
  • STOPPED – A stop operation was issued, or federation was set to start in the stopped state. Stopped states – Federation is not federating data to the destination, nor is it keeping a backlog of changes to send to the destination.  A “start” operation must be performed to start federating data again:
  • ERROR – An error occurred from which federation was unable to continue federating data
Paused state – Federation is not federating data, but is keeping a (growing) backlog of changes to be sent once a “start” operation is issued:
  • PAUSED – A pause operation was issued, or federation was set to start in the paused state.
Normal states – Federation is federating data:
  • INITIAL – default startup state.  A Coherence node will stay in this state until there is data to be federated
  • IDLE – federation is active and connected to the destination.  There is no data currently to send
  • READY – federation is transitioning out of CONNECTING, or YIELDING, or BACKLOG_NORMAL and will go to SENDING
  • SENDING – federation has data to send
  • CONNECTING – federation is connecting to the destination cluster
  • CONNECT_WAIT – federation is disconnected and will make a new connect attempt.  There may be a delay before making the next attempt depending on the circumstances under which federation was disconnected
  • YIELDING – federation has data to send, but is pausing briefly, likely due to a BACKLOG_EXCESSIVE event
  • DISCONNECTED – federation was disconnected from the remote destination.  If there is no data to send, federation may stay in this state. NB: DISCONNECTED is a “normal” state.  It means that a member of the cluster lost its federation connection to the remote cluster (probably because the remote member it was connected to was shut down).  If the member in the DISCONNECTED state has no data to send, it will stay in the DISCONNECTED state – basically the same as being IDLE.  Once there is some data for this member to send it will issue a new connection.
The following states do not exist – although they may have in (federation should not be used with this version):

Proxmox: enp0s31f6: Detected Hardware Unit Hang

Since a few weeks, my Proxmox lab has started having issues with on-board network. The adapter enters in “hang” state, the logs are full of recurring errors like below:

Initially I was suspecting a hardware issue but after replacing the motherboard, the problem still persisted.

Next, I’ve found this thread in Proxmox forum. Workaround which is suggested there seems to be working, below how I’ve implemented it:

One time fix

Preserve the change across reboots

Reboot and verify


Prevent Mac hidden files being written to a shared storage

MacOS tends to trash mounted disks with number of useless hidden files (e.g.  ._* or .DS_Store ). There were number of recipes in the Internet, some of them were working at some of time but are not anymore.

Below notes from my fights (at a moment of writing, on MacOS High Sierra 10.13.4 (17E199).

Removing the files when they are created

I used to apply a find . -name ... -print0 | xargs rm -0  combo but found that there is an built-in command to deal with these files:

From the man:

Preventing creating the files

On the MacOS side

NOTE: None of these solutions worked for me!

As I wrote, this didn’t work at all to me.

On the SMB server side

It actually turned the only working solution for me. Just add to the share configuration section a veto file parameter, e.g.:

And restart:

Note, after applying this change you will not be able anymore to use dot_clean  command from your Mac as any requests towards these files (including deletion) will be silently ignored by your SMB server hence files will remain untouched!

Oracle 12c 32-bit client and direct GOT relocation R_386_GOT32 against `lxecerr’

Edit 12/09/2018

As Ivan commented below:

with binutils release 27.28 it seems to be solved.

But see the workaround below in case it’s not…

When trying to install Oracle 12c 32-bit Client (12.1 or 12.2) on Oracle Linux 7.3 or 7.5, it throws error during linking static libraries:


Not very specific, I found only one reference in Oracle KM Doc ID 2246237.1.

Rootcause and resolution in there was:


SLES 12 SP2 ships with binutils 2.26 which breaks compatibility for certain shared library links.

01) Update binutils package to version binutils-2.26.1-9.15.1 or later.

But in fact, I do have in my server  binutils-2.27-27.base.el7.x86_64 .

Workaround is to downgrade the binutils:

After this, the libs can be compiled and linked:

I do believe that after finishing the installation, binutils can be upgraded again to the latest version (but not forget about this problem in case of installing the RSU).

PS: I’ve raised SR 3-17356002141 : Error when installing Oracle 32-bit client (direct GOT relocation R_386_GOT32 against `ipp_zcalloc’)


Belkin KVM: Falied to validate certificate

After one of JVM updates, my Belkin KVM (Remote IP Manager) has started refusing to start with “Falied to validate certificate” error followed by “PKIX path validation failed”:

I’ve found following exceptions in Java console:




Google says that this is pretty common problem and returned plenty of receipts how to fix it.

Scanning the system for potential locations of the file, there are four candidates. However, there is a catch: we should fix Java not in the system-wide location but the Java plugin for the web browser you’re using (Safari on MacOS in my case).


So we can skip the last three locations and just focus on the 1st one. Change the lines as described


Save and restart the browser (Safari). This time the KVM applet can start (after plenty of security warnings though).


The application has to be also white-listed, otherwise it will generate error as below:

Open System Preferences, Java settings and add IP address of your KVM to the list:

Add following:

Again: save and restart your browser.

Update 2

Another security exception is required (after one of Java 8 updates):


Edit this config file:

Add this line within the grant { }; section: