What’s new in RHEL7: Persistent journal log

Systemd journal logs are by default not persistent. They are stored in memory (kernel ring buffer) are /run/log/journal. This means, journal logs are available only from the current boot.

# journalctl --list-boots
0 f27172ee431b4012af52b7623468e2fc Fri 2016-10-21 06:16:53 CDT—Fri 2016-10-21 06:17:22 CDT

Logs from previous boot are not available. However, since journal logs are forward to rsyslog are default, you can still see journal logs from previous boot from /var/log/messages. You will not be able to view logs from previous boots using the journalctl command. Continue reading “What’s new in RHEL7: Persistent journal log”

What’s new in RHEL7: Persistent journal log

What’s new in RHEL7: Chrony

NTP service is provided by Chrony.

[root@rtfmp ~]# yum info chrony
Name        : chrony
Arch        : x86_64
Version     : 2.1.1
Release     : 1.el7.centos
Size        : 280 k
Repo        : base/7/x86_64
Summary     : An NTP client/server
URL         : http://chrony.tuxfamily.org
License     : GPLv2
Description : A client/server for the Network Time Protocol, this program keeps
            : your computer's clock accurate. It was specially designed to
            : support systems with intermittent internet connections, but it
            : also works well in permanently connected environments. It can use
            : also hardware reference clocks, system real-time clock or manual
            : input as time references.

If it is not installed, install it using Continue reading “What’s new in RHEL7: Chrony”

What’s new in RHEL7: Chrony

Reset IMM to factory default via LanOverUsb

We are going to upgrade a handful of ESX 4.1 hosts to 5.5 or 6, if the hardware supports. It is going to be a two step process, the first of which will be upgrade to 5.1 using the ISO. We need console access to do this. These are X series IBM servers. A part of our pre-upgrade checklist is to ensure we have IMM access.

We have one server where we cannot reach the IMM remotely. We have seen this before and managed to solve it by resetting the IMM via LanOverUsb or cold restart of the server- graceful shutdown of ESX(i), followed by unplug, plug both power supplies but not this time.
Continue reading “Reset IMM to factory default via LanOverUsb”

Reset IMM to factory default via LanOverUsb

Create a vSwitch, add uplink NIC and portgroup using esxcli

esxcli network vswitch standard add --vswitch-name=vSwitch1;
esxcli network vswitch standard uplink add --uplink-name=vmnic2 --vswitch-name=vSwitch1; 
esxcli network vswitch standard uplink add --uplink-name=vmnic3 --vswitch-name=vSwitch1;
esxcli network vswitch standard portgroup add --portgroup-name=vmNIC_vss_700  --vswitch-name=vSwitch1;
esxcli network vswitch standard portgroup set -p vmNIC_vss_700 --vlan-id 700;
Create a vSwitch, add uplink NIC and portgroup using esxcli

What’s new in RHEL7: Viewing the journal

In a Linux distro using systemd such as RHEL7, you can view the logs by rumning journalctl.

# journalctl
-- Logs begin at Sun 2016-09-25 00:00:38 CDT, end at Wed 2016-10-12 05:37:48 CDT. --
Sep 25 00:00:38 server.example.com systemd-journal[232]: Runtime journal is using 8.0M (max allowed 802.0M, trying to leave 1.1G free
Sep 25 00:00:38 server.example.com systemd-journal[232]: Runtime journal is using 8.0M (max allowed 802.0M, trying to leave 1.1G free
Sep 25 00:00:38 server.example.com kernel: Initializing cgroup subsys cpuset
Sep 25 00:00:38 server.example.com kernel: Initializing cgroup subsys cpu
...Truncated

The output will be very similar to what you see when you run “cat /var/log/messages”. You can scroll up and down and search by typing / because journalctl uses less pager. You will notice that errors are highlighted in red. Continue reading “What’s new in RHEL7: Viewing the journal”

What’s new in RHEL7: Viewing the journal