Demo: https://asciinema.org/a/201198

kube_functions.bash

function kpod() {
    local CMD=(kubectl get pods --no-headers)
    local NAMESPACE="$1"
    if [ -n "$NAMESPACE" ]; then
        CMD+=(--namespace "$NAMESPACE")
    fi
    "${CMD[@]}" | fzf --select-1 | awk '{print $1}'
}

function kcontainer() {
    local POD="$1"
    local NAMESPACE="$2"
    if [ -z "$POD" ]; then
        echo "Must specify pod!"
        return 1
    fi

    local CMD=(kubectl get pod "$POD" -o json)
    if [ -n "$NAMESPACE" ]; then
        CMD+=(--namespace "$2")
    fi

    local CONTAINERS="$(${CMD[@]} | jq -r '.spec.containers[].name')"
    local CONTAINER="$(echo "$CONTAINERS" | fzf --select-1)"

    if [ "$CONTAINER" == "" ]; then
        echo "Must specify container for pod $POD. Choices: ${$(echo $CONTAINERS | paste -sd ', ' -)}"
        return 1
    fi

    echo "$CONTAINER"
}

function kexec() {
    local POD
    local CONTAINER
    local NAMESPACE
    local PARAMS=()

    while [ $# -gt 0 ]; do
        local key="$1"
        local value="$2"
        case "$1" in
            -p|--pod)
                POD=$value
                shift 2
                ;;
            -c|--container)
                CONTAINER=$value
                shift 2
                ;;
            -n|--namespace)
                NAMESPACE=$value
                shift 2
                ;;
            --) # end argument parsing and pass the rest as arguments to the logs command
                shift
                PARAMS+=($@)
                break
                ;;
            -*|--*=) # unsupported flags
                echo "Error: Unsupported flag $key" >&2
                return 1
                ;;
            *) # preserve positional arguments
                PARAMS+=("$key")
                shift
                ;;
        esac
    done
    # set positional arguments in their proper place
    set -- "${PARAMS[@]}"

    if [ -z "$POD" ]; then
        POD="$(kpod "$NAMESPACE")"
        local RET=$?
        if [ $RET -ne 0 ]; then
            echo "$POD"
            return $CODE
        fi
    fi

    if [ -z "$POD" ]; then
        echo "Must specify pod!"
        return 1
    fi

    if [ -z "$CONTAINER" ]; then
        CONTAINER="$(kcontainer "$POD" "$NAMESPACE")"
        local RET=$?
        if [ $RET -ne 0 ]; then
            echo "$CONTAINER"
            return $CODE
        fi
    fi

    if [ -z "$CONTAINER" ]; then
        echo "Must specify container!"
        return 1
    fi

    local COLUMNS=$(tput cols)
    local LINES=$(tput lines)
    local TERM=xterm
    local EXEC_CMD=(kubectl exec -i -t "$POD" -c "$CONTAINER")
    if [ -n "$NAMESPACE" ]; then
        EXEC_CMD+=(--namespace "$NAMESPACE")
    fi

    # test if bash exists, if it does, we'll use bash, otherwise use sh
    "${EXEC_CMD[@]}" -- test -e /bin/bash 2> /dev/null
    if [ $? -eq 0 ] ; then
        local KUBE_SHELL=${KUBE_SHELL:-/bin/bash}
    else
        local KUBE_SHELL=${KUBE_SHELL:-/bin/sh}
    fi

    EXEC_CMD+=(-- "$KUBE_SHELL")
    # if arguments are passed, then invoke our shell with -c, otherwise just
    # start an interactive login shell
    if [ $# -gt 0 ]; then
        EXEC_CMD+=(-c "$*")
    else
        EXEC_CMD+=(-il)
    fi
    echo "${EXEC_CMD[@]}"
    "${EXEC_CMD[@]}"
}

function klogs() {
    local POD
    local CONTAINER
    local NAMESPACE
    local PARAMS=()

    while [ $# -gt 0 ]; do
        local key="$1"
        local value="$2"
        case "$1" in
            -p|--pod)
                POD=$value
                shift 2
                ;;
            -c|--container)
                CONTAINER=$value
                shift 2
                ;;
            -n|--namespace)
                NAMESPACE=$value
                shift 2
                ;;
            --) # end argument parsing and pass the rest as arguments to the logs command
                shift
                PARAMS+=($@)
                break
                ;;
            -*|--*=) # unsupported flags
                echo "Error: Unsupported flag $key" >&2
                return 1
                ;;
            *) # preserve positional arguments
                PARAMS+=("$key")
                shift
                ;;
        esac
    done
    # set positional arguments in their proper place
    set -- "${PARAMS[@]}"

    if [ -z "$POD" ]; then
        POD="$(kpod "$NAMESPACE")"
        local RET=$?
        if [ $RET -ne 0 ]; then
            echo "$POD"
            return $CODE
        fi
    fi

    if [ -z "$POD" ]; then
        echo "Must specify pod!"
        return 1
    fi

    if [ -z "$CONTAINER" ]; then
        CONTAINER="$(kcontainer "$POD" "$NAMESPACE")"
        local RET=$?
        if [ $RET -ne 0 ]; then
            echo "$CONTAINER"
            return $CODE
        fi
    fi

    if [ -z "$CONTAINER" ]; then
        echo "Must specify container!"
        return 1
    fi

    local LOGS_CMD=(kubectl logs "$POD" -c "$CONTAINER")
    if [ -n "$NAMESPACE" ]; then
        LOGS_CMD+=(--namespace "$NAMESPACE")
    fi
    LOGS_CMD+=("$@")
    echo "${LOGS_CMD[@]}"
    "${LOGS_CMD[@]}"
}