erikdw

Metaspace Research

What is PermGen?

• The Permanent Generation memory pool contains permanent class metadata and descriptors information when classes are loaded
  • PermGen space is always reserved for classes and items that are attached to them (i.e., static members)
• PermGem space is contiguous in memory to the Java heap and have the same rounds of Garbage Collection but it is not part of the Java heap

What is Metaspace?

• In JDK8, the PermGen space has been entirely replaced by Metaspace which is no longer contiguous to the Java heap and now exists in native memory

erikdw

-- Usage: tshark -X lua_script:statsd_dissector.lua -r capture.pcap
-- Usage: tshark -X lua_script:statsd_dissector.lua -T fields -e statsd.metric_name -e statsd.value -e statsd.metric_type -e stats.metric_tags -r capture.pcap

local statsd = Proto("statsd","Statsd Protocol")

local pf_metric_name = ProtoField.new("Metric Name", "statsd.metric_name", ftypes.STRING)
local pf_value = ProtoField.new("Value", "statsd.value", ftypes.STRING)
local pf_metric_type = ProtoField.new("Metric Type", "statsd.metric_type", ftypes.STRING)
local pf_metric_tags = ProtoField.new("Metric Tags", "statsd.metric_tags", ftypes.STRING)

erikdw

Raw version of https://github.com/erikdw/tips-and-tricks/wiki/Tips-and-Tricks without ugly formatting.

1. SSH break-out:

    ```
    <enter>~.
    <enter>~?
    ```

2. Shadowed window screenshot in mac:

erikdw

(13) tcpdumps:  (no -s 65535 needed on recent tcpdumps)

  (a) find dns requests (adjusted for being on hosts in terremark):
     sudo tcpdump -i eth1 -c3000 -l -n dst port 53 | grep api
       (thepoint@tm22-s00311)

     sudo tcpdump -i eth0 -c3000 -l -n port 3133

  (b) capture all data:

erikdw

javascript:
document.querySelectorAll('.load-diff-button').forEach(node => node.click());
document.querySelectorAll('.js-details-target').forEach(node => node.click());

// Both of those buttons should have the '.btn-link' class too, but I wasn't able to quickly figure out how to
// add an AND condition to that.  Tried the below, didn't work:
//document.querySelectorAll('[.btn-link][.load-diff-button]').forEach(node => node.click());

erikdw

⚠️ 😱

🟢

:blue_circle:

🔵

erikdw

Process:               com.pallotron.yubiswitch.helper [2984]
Path:                  /Library/PrivilegedHelperTools/com.pallotron.yubiswitch.helper
Identifier:            com.pallotron.yubiswitch.helper
Version:               1.0
Code Type:             X86-64 (Native)
Parent Process:        launchd [1]
Responsible:           yubiswitch [731]
User ID:               0

erikdw

• #1589F0
• #1589F0
• !(https://placehold.it/15/1589F0/000000?text=+) #1589F0

🔵

first arrow ➡

second arrow

erikdw

# input vars
variable "environment" {
  default = "Dev"
}

# local vars
locals {
  name     = "hello"
  env      = "${lower(var.environment)}"
  lb_name  = "${join("-", list("TF", var.environment, local.name))}"

erikdw

<project>
    ...
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <executions>
                    <execution>
                        <phase>package</phase>